1 and the number itself

In your book, Maths Mela (Chapter 13, Animal Jumps), we found that the factors of 12 are 1, 2, 3, 4, 6 and 12. Look at the first and the last: 1 and 12. The book fills in 1 × 12 = 12 and 12 × 1 = 12.

This works for every number. Any number of squares can be put in one single row: 1 row of 20 is 1 × 20 = 20, and 1 row of 46 is 1 × 46 = 46. So 1 is always a factor, and the number itself is always a factor too. The book says: the number itself and 1 are always factors of any number.

There is one more thing to notice. Since 12 × 1 = 12, the number 12 is a multiple of 12. The book says: the number itself is always a multiple of itself. So 25 is a multiple of 25, and 54 is a multiple of 54.

When you list the factors of a number, you can start with these two for free. For 20, write 1 and 20 first, then look for the others: 2 × 10 and 4 × 5. So the factors of 20 are 1, 2, 4, 5, 10 and 20.