Solving Word Problems with Positive and Negative Fractions

This lesson teaches how to solve word problems involving positive and negative fractions using mathematical reasoning. It highlights common mistakes students make, such as providing unreasonable answers. The lesson uses a cupcake recipe example to demonstrate solving a problem by doubling the recipe and using proportions. It emphasizes the importance of ensuring the solution is reasonable and answers the original question, concluding that Janie needs an additional 1 1/2 cups of sugar to make 36 cupcakes.

What is a common mistake students make when solving word problems involving fractions?

How much sugar does Janie need to make 36 cupcakes according to the recipe?

Explain how Janie can use a proportion to find out how much sugar she needs.

What steps did Janie take to ensure her final answer was reasonable?

After calculating, how much additional sugar does Janie need?