Some More Divisibility Rules

Some More Divisibility Rules:

a) Common divisibility examples:

Let us observe a few more rules about the divisibility of numbers.

1. If a number is divisible by another number then it is divisible by each of the factors of that number. Consider 24. It is divisible by 8 and the factors of 8 i.e. 1, 2, 4, and 8 also divide 24.

2. If a number is divisible by two co-prime numbers then it is divisible by their product also. The number 80 is divisible by 4 and 5. It is also divisible by 4 × 5 = 20, and 4 and 5 are co-primes.
   Similarly, 60 is divisible by 3 and 5 which are co-primes. 60 is also divisible by 3 × 5 = 15.

3. If two given numbers are divisible by a number, then their sum is also divisible by that number. The numbers 16 and 20 are both divisible by 4. The number 16 + 20 = 36 is also divisible by 4.

4. If two given numbers are divisible by a number, then their difference is also divisible by that number. The numbers 35 and 20 are both divisible by 5. Is their difference 35 – 20 = 15 also divisible by 5.