Nika baked three cakes. Each cake needed 17/4 cups of flour. Which expression shows the best estimate of the number of cups of flour that Nika used?

A. 4 + 4 + 4 = 12

B. 5 + 5 + 5 = 15

C. 4 + 4 + 4 = 16

D. 17 + 17 + 17 = 51

The answer would be C.

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.