If you rewrite this phrase to be an equation, with N representing the missing number, it would be:
20% x N = 1581.01 or 0.2N = 1581.01
This equation basically says 20% of what number equals 1581.01.
To get to the answer, divide both sides by 0.2. -->
0.2N ÷ 0.2 = 1581.01 ÷ 0.2 -->
N = 1581.01/0.2
N = 7905.05
