Secondary 1 G1 Mathematics Tutor Bukit Timah. Did you know? Factors divide exactly, while multiples grow by repeated multiplication. Learn the difference before tackling prime numbers. A short, practical guide for Singapore parents and students, with clear worked examples and a quick way to check understanding.
The best question to begin with is: What does this symbol or relationship actually mean? The answer often reveals more about learning than one correct result on a worksheet.
Did you know? Six can be a factor and a multiple
Did you know? The number 6 is a factor of 24 and a multiple of 3 at the same time. That is not a contradiction. The two words describe different relationships. In Secondary 1 G1 Mathematics, this distinction helps pupils reason about prime numbers and whole-number operations.
A factor divides a number exactly, leaving no remainder. A multiple is a number you obtain by multiplying by a whole number. Saying the whole relationship aloud is more useful than trying to memorise two unrelated definitions.
Factors: ask whether the division is exact
Take 18. Because 18 ÷ 3 = 6 with no remainder, 3 is a factor of 18. Because 18 ÷ 5 does not give a whole number, 5 is not a factor of 18.
Write the positive factor pairs of 18: 1 × 18, 2 × 9 and 3 × 6. From these pairs, the positive factors are 1, 2, 3, 6, 9 and 18. Using pairs helps a pupil see that factors come in complementary partners.
Try a quick check for 20: the pairs are 1 × 20, 2 × 10 and 4 × 5. So the positive factors are 1, 2, 4, 5, 10 and 20. This is arithmetic with a reason, rather than guesswork.
Multiples: start with repeated groups
The positive multiples of 4 begin 4, 8, 12, 16, 20. They are 4 × 1, 4 × 2, 4 × 3, 4 × 4 and 4 × 5. Another way to see them is to keep adding four.
The number 20 is a multiple of 4 because 4 × 5 = 20. The same fact tells you that 4 is a factor of 20. Those statements point to the same relationship from opposite directions.
A common mistake is to list 4, 8 and 12 as factors of 4. They are multiples. A helpful phrase is: “Factors fit into a number; multiples come from its times table.”
How this helps with prime numbers
A prime number has exactly two distinct positive factors: 1 and itself. For example, 13 has only 1 and 13. It is prime. By contrast, 15 has 1, 3, 5 and 15, so it is composite.
Notice how factor checking answers the prime-number question. You do not need a complicated procedure. If you find a positive factor other than 1 and the number itself, it cannot be prime.
Important for parents: the official Secondary 1 G1 Mathematics syllabus includes prime numbers but excludes prime factorisation in this section. Knowing elementary factor relationships supports the work; lengthy prime-factor trees and HCF/LCM procedures should not automatically be treated as required G1 Secondary 1 content.
A good tutor checks the first decision
Imagine a pupil says “21 is prime because it is odd.” Rather than supplying the answer immediately, ask whether 21 can be arranged in three equal groups. Since 3 × 7 = 21, 21 has more than two positive factors and is not prime.
Another pupil may know that 3 divides 21 but still confuse whether 21 is a factor of 3. That learner needs help stating the direction of the relationship. The correction should be specific.
eduKateSG’s published Secondary 1 Mathematics tutorial model near Sixth Avenue MRT uses groups of up to three pupils with 1.5-hour weekly lessons and close checking. In a small group, a tutor can ask each learner to explain one factor pair and independently test another number.
Five-minute number sense check
Question 1: List the positive factors of 12. Answer: 1, 2, 3, 4, 6 and 12. Question 2: Write the next two multiples after 5, 10, 15. Answer: 20 and 25. Question 3: Is 21 prime? Answer: no, because 3 × 7 = 21.
Ask your child to explain why an answer is a factor or a multiple. If they can verify it using division or multiplication, they have more than an answer-key memory.
Frequently asked questions
Is factor checking useful for Secondary 1 G1? Yes. It provides a simple way to understand the prime-number definition. Keep the depth matched to the G1 school syllabus.
What is the difference between a factor and a multiple? A factor divides a number exactly; a multiple results from multiplying by a whole number.
Does G1 Secondary 1 require prime factorisation? The MOE G1 Secondary 1 syllabus explicitly excludes prime factorisation from its introductory prime-number content.
Read next: related Secondary 1 G1 Mathematics guides
- Ratio Sharing When One Part Is Known
- Corresponding, Alternate and Interior Angles
- Substitution with Negative Numbers and Brackets
- Prime Numbers: Why One Is Not Prime
For the existing tuition approach, see the original eduKateSG Secondary 1 Mathematics tutorial guide. It describes three-student lessons near Sixth Avenue MRT, 1.5-hour weekly teaching, focused practice and corrections. The reference page remains unchanged.
The Ministry of Education G1 Mathematics syllabus sets the subject scope. G1 is a subject level under Full Subject-Based Banding, not a fixed measure of a child’s potential. The actual sequence of school lessons and assessments can vary.
For parents in Bukit Timah, a marked Maths question can be a useful starting point for discussing which step needs repair. Contact eduKate Singapore to enquire about suitable current G1 groups, timing and availability.