or
or
We know, divident = quotient x divisor + remainder
So, divident = quotient x 105 + 99
Now, 105 is completely divisible by 21 yielding the quotient 5. So, we only need to divide the remainder 99 by 21 to see if any remainder remains.
Now, 99 = 4 x 21 + 15. So, 15 will be remained as a remainder if the number is divided by 21 instead of 105.
