Chapter 6 · CBSE Class 5 Maths (NCERT Math-Magic)

Be My Multiple, I'll be Your Factor

Play a number game of factors and multiples to discover which numbers are prime, and which numbers share common factors.

🔢 Chapter 6

Numbers 1 to 20 with the factors of 20 highlighted A grid of numbers from 1 to 20, with the six factors of 20 (1, 2, 4, 5, 10, and 20) shown as solid teal circles with white text, and the remaining non-factor numbers shown as plain outlined circles 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 factor of 20
6.1

Factors and Multiples

A factor of a number divides it exactly, with no remainder. A multiple of a number is what you get when you multiply it by a whole number — so multiples go on forever, but factors are limited.

1

List all the factors of 12.

1, 2, 3, 4, 6, 12

2

List the first 5 multiples of 4.

4, 8, 12, 16, 20

6.2

Prime and Composite Numbers

A prime number has exactly two factors: 1 and itself. A composite number has more than two factors. The number 1 is neither prime nor composite.

1

Is 17 a prime number?

Yes, its only factors are 1 and 17

2

Is 15 prime or composite?

Composite — its factors are 1, 3, 5, and 15

Practice

Exercises

1. List all the factors of 20.

2. List the first 4 multiples of 7.

3. Is 23 prime or composite?

4. Is 21 prime or composite?

5. What is the smallest common factor that any two numbers always share?

Next chapter — Chapter 7: Can You See the Pattern? 🔁 →