Word problem: A recipe for making cookies use half cup of sugar for 1 cup of flour to make one pound of cookies. How many cups of sugar you need to make 3 pound of cookies.
As you can see to solve that problem you need to multiply the fraction 1/2, which is the number of cups needed to make 1 pound of cookies, times the number of pounds that you want to make.
So, for this problem you have to multiply 1/2 times 3.