Quick answer: For P4 number-pattern questions, compare neighbouring terms, identify a consistent rule and check it against every given term before filling a gap. Do not assume that a rule fits simply because it explains the first pair of numbers.
This is a Singapore P4 Mathematics school-assessment and learning guide on number patterns and missing terms. It offers twenty worked examples, parent explanations, independent practice, a revision sequence and common errors. There is no national SEAB P4 Mathematics paper: schools set their assessments under the MOE syllabus. These are original teaching examples, not predictions of future 2027 questions.
- Read the exact target and the units before choosing an operation.
- Use a short representation or explanation when it clarifies the relation.
- Estimate or check independently where possible.
- Keep the school’s actual taught scope and assessment instructions in view.
- Retest a corrected misconception on a different question after a delay.
How this topic fits the MOE Primary Mathematics curriculum
The MOE Primary Mathematics Syllabus, updated October 2025 sets the P4 content and broader processes of reasoning, problem solving, communication and metacognition. For P4 number-pattern questions, compare neighbouring terms, identify a consistent rule and check it against every given term before filling a gap. Do not assume that a rule fits simply because it explains the first pair of numbers. A school may emphasise different strands at different points in the year. Parents should consult the latest assessment notice rather than assume a fixed national P4 paper format.
A good learning sequence begins with the meaning of the problem, uses a simple model if needed, and ends with a changed independent question. Copying a worked solution immediately after seeing it can create an illusion of understanding. Independent transfer and a delayed retest provide better evidence that the child can apply the method without prompts.
Twenty original worked examples and detailed checking methods
Worked example 1: 125, 150, 175, __, 225
Answer: 200. Working or reasoning: Add 25 each time.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Add 25 each time. Ask the student to name the unknown and the relevant unit, then check whether 200 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 2: 960, 880, 800, __, 640
Answer: 720. Working or reasoning: Subtract 80 each time.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Subtract 80 each time. Ask the student to name the unknown and the relevant unit, then check whether 720 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 3: 3, 6, 12, 24, __
Answer: 48. Working or reasoning: Double each term.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Double each term. Ask the student to name the unknown and the relevant unit, then check whether 48 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 4: 5, 15, 45, __
Answer: 135. Working or reasoning: Multiply by 3.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Multiply by 3. Ask the student to name the unknown and the relevant unit, then check whether 135 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 5: 2, 7, 12, 17, __
Answer: 22. Working or reasoning: Add 5.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Add 5. Ask the student to name the unknown and the relevant unit, then check whether 22 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 6: 1000, 900, 800, __
Answer: 700. Working or reasoning: Subtract 100.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Subtract 100. Ask the student to name the unknown and the relevant unit, then check whether 700 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 7: 7, 14, 21, __, 35
Answer: 28. Working or reasoning: Multiples of 7.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Multiples of 7. Ask the student to name the unknown and the relevant unit, then check whether 28 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 8: 8, 16, 24, __, 40
Answer: 32. Working or reasoning: Multiples of 8.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Multiples of 8. Ask the student to name the unknown and the relevant unit, then check whether 32 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 9: 1, 4, 9, 16, __
Answer: 25. Working or reasoning: Square numbers.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Square numbers. Ask the student to name the unknown and the relevant unit, then check whether 25 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 10: 11, 22, 33, __, 55
Answer: 44. Working or reasoning: Add 11.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Add 11. Ask the student to name the unknown and the relevant unit, then check whether 44 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 11: 5, 10, 20, 40, __
Answer: 80. Working or reasoning: Double.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Double. Ask the student to name the unknown and the relevant unit, then check whether 80 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 12: 320, 280, 240, __
Answer: 200. Working or reasoning: Subtract 40.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Subtract 40. Ask the student to name the unknown and the relevant unit, then check whether 200 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 13: 13, 23, 33, 43, __
Answer: 53. Working or reasoning: Add 10.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Add 10. Ask the student to name the unknown and the relevant unit, then check whether 53 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 14: 2, 4, 8, 16, 32, __
Answer: 64. Working or reasoning: Double.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Double. Ask the student to name the unknown and the relevant unit, then check whether 64 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 15: 4, 9, 14, __, 24
Answer: 19. Working or reasoning: Add 5.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Add 5. Ask the student to name the unknown and the relevant unit, then check whether 19 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 16: 72, 64, 56, __
Answer: 48. Working or reasoning: Subtract 8.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Subtract 8. Ask the student to name the unknown and the relevant unit, then check whether 48 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 17: 1, 3, 6, 10, __
Answer: 15. Working or reasoning: Differences 2,3,4,5.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Differences 2,3,4,5. Ask the student to name the unknown and the relevant unit, then check whether 15 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 18: 2, 5, 10, 17, __
Answer: 26. Working or reasoning: Differences 3,5,7,9.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Differences 3,5,7,9. Ask the student to name the unknown and the relevant unit, then check whether 26 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 19: 50, 100, 150, __
Answer: 200. Working or reasoning: Add 50.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Add 50. Ask the student to name the unknown and the relevant unit, then check whether 200 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Worked example 20: 81, 72, 63, __
Answer: 54. Working or reasoning: Subtract 9.
This question is useful because the correct solution depends on identifying the mathematical relationship, not just the visible digits. Subtract 9. Ask the student to name the unknown and the relevant unit, then check whether 54 is consistent with the given condition. Where the result is an estimate, distinguish approximate from exact equality. Where the result is a measurement, make sure the unit describes the quantity.
For transfer, change one of the numbers or alter the question’s requested target. The student should explain whether the same method still applies and why. If the child hesitates, return to a smaller example and make the mathematical relationship visible before attempting harder work. This avoids repeating the same error under a different story.
Four common mistakes and targeted corrections
Mistake 1: A rule that fits only the first two terms may not fit the whole sequence.
Locate the first step at which the student’s interpretation, operation or answer ceased to fit the question. Do not use ‘careless’ as a substitute for diagnosis. A specific explanation lets the child practise the missing skill directly. A useful correction includes one contrasting example and one new question solved without adult prompts.
Record the original error, corrected idea and delayed retest result. If the child still cannot explain the solution independently, simplify the example and rebuild the prerequisite. Progress should be measured by accurate new work, not by copying a model or finishing a high volume of worksheets.
Mistake 2: A descending sequence needs subtraction or division, not always addition.
Locate the first step at which the student’s interpretation, operation or answer ceased to fit the question. Do not use ‘careless’ as a substitute for diagnosis. A specific explanation lets the child practise the missing skill directly. A useful correction includes one contrasting example and one new question solved without adult prompts.
Record the original error, corrected idea and delayed retest result. If the child still cannot explain the solution independently, simplify the example and rebuild the prerequisite. Progress should be measured by accurate new work, not by copying a model or finishing a high volume of worksheets.
Mistake 3: Missing terms should be checked with both neighbours.
Locate the first step at which the student’s interpretation, operation or answer ceased to fit the question. Do not use ‘careless’ as a substitute for diagnosis. A specific explanation lets the child practise the missing skill directly. A useful correction includes one contrasting example and one new question solved without adult prompts.
Record the original error, corrected idea and delayed retest result. If the child still cannot explain the solution independently, simplify the example and rebuild the prerequisite. Progress should be measured by accurate new work, not by copying a model or finishing a high volume of worksheets.
Mistake 4: Some patterns have changing differences; compare differences rather than guessing.
Locate the first step at which the student’s interpretation, operation or answer ceased to fit the question. Do not use ‘careless’ as a substitute for diagnosis. A specific explanation lets the child practise the missing skill directly. A useful correction includes one contrasting example and one new question solved without adult prompts.
Record the original error, corrected idea and delayed retest result. If the child still cannot explain the solution independently, simplify the example and rebuild the prerequisite. Progress should be measured by accurate new work, not by copying a model or finishing a high volume of worksheets.
Independent practice and answer key
Practice 1: 125, 150, 175, __, 225. Answer: 200. Check: Add 25 each time. Cover the answer first, solve independently and compare the reasoning.
Practice 2: 960, 880, 800, __, 640. Answer: 720. Check: Subtract 80 each time. Cover the answer first, solve independently and compare the reasoning.
Practice 3: 3, 6, 12, 24, __. Answer: 48. Check: Double each term. Cover the answer first, solve independently and compare the reasoning.
Practice 4: 5, 15, 45, __. Answer: 135. Check: Multiply by 3. Cover the answer first, solve independently and compare the reasoning.
Practice 5: 2, 7, 12, 17, __. Answer: 22. Check: Add 5. Cover the answer first, solve independently and compare the reasoning.
Practice 6: 1000, 900, 800, __. Answer: 700. Check: Subtract 100. Cover the answer first, solve independently and compare the reasoning.
Practice 7: 7, 14, 21, __, 35. Answer: 28. Check: Multiples of 7. Cover the answer first, solve independently and compare the reasoning.
Practice 8: 8, 16, 24, __, 40. Answer: 32. Check: Multiples of 8. Cover the answer first, solve independently and compare the reasoning.
Practice 9: 1, 4, 9, 16, __. Answer: 25. Check: Square numbers. Cover the answer first, solve independently and compare the reasoning.
Practice 10: 11, 22, 33, __, 55. Answer: 44. Check: Add 11. Cover the answer first, solve independently and compare the reasoning.
Practice 11: 5, 10, 20, 40, __. Answer: 80. Check: Double. Cover the answer first, solve independently and compare the reasoning.
Practice 12: 320, 280, 240, __. Answer: 200. Check: Subtract 40. Cover the answer first, solve independently and compare the reasoning.
Practice 13: 13, 23, 33, 43, __. Answer: 53. Check: Add 10. Cover the answer first, solve independently and compare the reasoning.
Practice 14: 2, 4, 8, 16, 32, __. Answer: 64. Check: Double. Cover the answer first, solve independently and compare the reasoning.
Practice 15: 4, 9, 14, __, 24. Answer: 19. Check: Add 5. Cover the answer first, solve independently and compare the reasoning.
Practice 16: 72, 64, 56, __. Answer: 48. Check: Subtract 8. Cover the answer first, solve independently and compare the reasoning.
Practice 17: 1, 3, 6, 10, __. Answer: 15. Check: Differences 2,3,4,5. Cover the answer first, solve independently and compare the reasoning.
Practice 18: 2, 5, 10, 17, __. Answer: 26. Check: Differences 3,5,7,9. Cover the answer first, solve independently and compare the reasoning.
Practice 19: 50, 100, 150, __. Answer: 200. Check: Add 50. Cover the answer first, solve independently and compare the reasoning.
Practice 20: 81, 72, 63, __. Answer: 54. Check: Subtract 9. Cover the answer first, solve independently and compare the reasoning.
A ten-session revision and home-learning sequence
- Session 1: collect recent schoolwork and identify the most common error.
- Session 2: explain one central concept with a concrete example.
- Session 3: solve two changed problems without hints.
- Session 4: compare a correct and an incorrect method.
- Session 5: practise the same concept in a different story.
- Session 6: mix it with a previously mastered P4 topic.
- Session 7: use an inverse operation, estimate or unit check.
- Session 8: complete a short untimed independent set.
- Session 9: introduce gentle timing only after accuracy is secure.
- Session 10: retest the original error after a gap and record progress.
This is an adaptable study routine rather than a compulsory school schedule. A child may need longer to master one prerequisite, or may already be ready for mixed practice. Families should preserve rest and ordinary routines, and follow the school for any upcoming assessment. A useful next step is one that repairs a demonstrated weakness.
Frequently asked questions for parents and students
Does Singapore have a national P4 Maths SEAB paper?
No. Primary 4 school assessments are distinct from the national P6 PSLE.
Will these exact questions appear in 2027?
No. They are original teaching examples and do not predict a school’s paper.
How should I select a revision topic?
Use the school’s scope and the first recurring error in marked work.
Is speed more important than accuracy?
Build accurate independent methods first; introduce manageable timing later.
Should a child memorise model answers?
No. The child should explain why the method fits and apply it to changed numbers.
How do I check whether a correction worked?
Give an unfamiliar question after a delay and remove prompts.
Can a bar model or table help?
Yes, when it clarifies the mathematical relationship and meets school instructions.
Should I assign more work after every mistake?
Not necessarily. Diagnose the error and choose focused practice.
What if a child is struggling with an earlier prerequisite?
Rebuild the earlier idea before increasing difficulty.
Can parents ask the teacher about assessment scope?
Yes. The school’s notice and teacher guidance are the relevant references.
Do all schools use identical question formats?
No. P4 assessment formats are school-based.
Where is the official syllabus?
The MOE Primary Mathematics Syllabus linked above.
How to check that a pattern rule really fits
A useful number-pattern habit is to test a proposed rule against every adjacent pair, not merely the first two. If a child sees 5, 10, 15, 20, the repeated addition of five explains each transition. If a sequence shows 2, 4, 8, 16, a doubling rule explains the transitions, while repeatedly adding two fails after the second term. A plausible rule must survive all the known values. For a missing middle term, test both the value before and the value after the gap.
Ask the child to say the rule in words and then apply it to a fresh term. When a pattern has increasing differences, such as 1, 3, 6, 10, the differences are 2, 3, 4, so the next difference is 5 and the next term is 15. This is a different structure from a fixed-step sequence. Use such examples to develop curiosity and reasoning, but follow the school’s taught scope for any immediate P4 assessment.
An answer can be numerically correct by coincidence. To check, ask why the next term follows and whether the same reasoning produces the preceding terms. A child who can explain the rule and test it independently is showing stronger understanding than one who merely guesses the next number.
Next reading and primary source
Read the related P4 Maths Error Checking Guide, P4 School Assessment and Revision Plan, and P4 Mixed Practice Paper. Official reference: MOE Primary Mathematics Syllabus. This article is an independent teaching resource.