First we need to find out what 17/4 is.
17/4 = 4 1/4
so each cake needs 4 1/4 cups of flower.
Now, the question asks what the best estimate of the total number of cups is.
It could be A or C because 4 1/4 is closer to 4, but...
we need to figure out if 4 1/4 + 4 1/4 + 4 1/4 (we need to make three cakes) is closer to 12 or 16.
4 1/4 + 4 1/4 + 4 1/4 = 12 3/4
Ask yourself: is 12 3/4 closer to 12 or 16?
12 3/4 is closer to 12 so the answer is A.
