What is 39 over 63 in simplest form?

To simplify the fraction 39 over 63, we need to find the greatest common divisor (GCD) of 39 and 63, which is 9. Dividing both the numerator and the denominator by 9 gives us 39 ÷ 9 = 4 and 63 ÷ 9 = 7. Therefore, the simplest form of the fraction 39 over 63 is 4 over 7.