Ms. Clark put icing on 1/3 of a batch of cupcakes. She let Mackenzie put icing on 1/4 of the remaining cupcakes.

A. What fraction of all of the cupcakes did Mackenzie out icing on?

B. What fraction of the cupcakes have no icing? **Solution****A.** If Ms. Clark put icing on 1/3 of a batch of cupcakes, then 1 - 1/3 of the batch of cupcakes do not have icing.

1 - 1/3 = 3/3 - 1/3 = 2/3

Then, Mackenzie put icing on 1/4 of 2/3.

1/4 of 2/3 = 1/4 × 2/3 = 2/12 = 1/6

Mackenzie put icing on 1/6 of the batch of cupcakes.**B.**

Clark and Mackenzie put icing on 1/3 and 1/6 of the batch of cupcakes.

1/3 + 1/6 = 2/6 + 1/6 = 3/6 = 1/2

Clark and Mackenzie put icing on 1/2 of the batch of cupcakes.

The fraction of the cupcakes that have no icing is 1 - 1/2.

1 - 1/2 = 2/2 - 1/2 = 1/2

The fraction of the cupcakes that have no icing is 1/2.