Division by zero:

Division by a number means subtracting that number repeatedly.
The division of a whole number by 0 is not defined.

i) Let us try 7 ÷ 0.

Again, we never get 0 at any stage of subtraction.

We say 7 ÷ 0 is not defined.

ii) Let us find 8 ÷ 2.

Subtract 2 again and again from 8.

So, we write 8 ÷ 2 = 4.