Because 1/5 has to be converted into the 100 as the denominator and the number you are supposed to have for the numerator so it can be easier and 4 is the whole number so it doesnt need to be in the equation.
1/5
X
20= 20/100 so now all you have to do is make that a decimal since it hasnt got to 100 or past it and you have your answer
