This lesson is from Tools for NC Teachers. Students explore a task using multiplicative reasoning. This is remixable. 

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A donut shop makes three times as many donuts as pastries. If the shop makes 186 donuts per day, how many pastries do they make? 

How can we compare the amount of donuts to the amount of pastries using models and equations with a symbol for the unknown?

Allow students time to solve and come up with ways to compare the donuts and pastries as stated above.  As students are solving, circulate and select students to share their work and comparisons.  See the examples below for various ways students may solve the problem.  Try to choose a variety of examples to share with the class.  As students briefly share the strategies, record their statements on chart paper or a white board as sentences and/or equations.

Examples:

There are three times as many donuts as pastries.          

3 x pastries = donuts     

3p = d       

186 = 3 x pastries                 

186 ÷ 3 = 62                   

 62 x 3 = 186

There are one third as many pastries as donuts.           

1/3 x donuts = pastries   

1/3d = p

If a student uses a model, be sure to have that student share.  If not, introduce the model as a way of solving the problem.  Be sure to explain the thinking behind the model.