Proportions 3 – Setting Up and Solving Proportions | Math Fluency

🔑 Key Ideas in Proportions 3 – Setting Up and Solving Proportions | Math Fluency

In Lesson 3, students solve proportion word problems easily using the Magic Formula. Students start off by writing the Magic Formula in the space provided to the right of the directions. The Magic Formula is:

a/b = a/b

The first problem has no a’s and b’s. Instead, there are shirts and jackets. The proportion is:

s/j = s/j

Students should leave enough space so that they have room to show their work.

As shown in the answer key and in the demo video, the answer to Box A is 54 shirts. Remember to include the units in answer. An answer of, “There are 54” would be insufficient. The correct answer is, “There are 54 shirts,” which you will notice answers the question, “How many shirts are there?”

Students also learn what to do when the problem doesn't give them the three out of four values that they need to solve a proportion (Box F).