Let's assume the number be x.
Hence, the problem is to find 20% of x that equal to 100.
Hence, we can set up the equation as following:
20% of x = 100
0.20 * x = 100 Since 20%= 20/100 = 0.20
Dividing each sides by 0.20 to isolate x.
So, x = 500 By simplifying.
Hence, the number is 500.