If you need 1 1/4 cups of sugar to make cookies, that is the amount of sugar needed for one batch of cookies. To find out how much sugar is needed to make 16 cookies, we can set up a proportion:
1 1/4 cups sugar is needed to make 1 batch of cookies
x cups sugar is needed to make 16 cookies
We can solve for x by cross-multiplying:
1 1/4 * 16 = x
20/4 = x
5 = x
Therefore, you will need 5 cups of sugar to make 16 cookies.