To simplify the fraction 100/20, you need to divide both the numerator (100) and the denominator (20) by their greatest common divisor (GCD).
In this case, the GCD of 100 and 20 is 20. So, you divide both the numerator and denominator by 20:
100 ÷ 20 = 5
20 ÷ 20 = 1
Thus, 100/20 simplifies to 5/1, which is just 5.
This means that the fraction 100/20 can be simplified to 5.