Getting Started

The student does not understand multiplicative comparisons.

The student multiplies the two numbers in each problem to solve. The student writes each equation as 18 x 6 = ___ and 20 x 5 = ___.

The student may solve one or both of the problems using addition (18 + 6 = _) or subtraction (18 – 6 =_ ).

How far did Sadie throw the football? How far did William throw it?

If William had thrown it twice as far, how far would it have gone?

How about Michael’s cards? How many did he have? Abed?

If Abed had twice (or three times) as many cards, how many cards would he have?

Expose the student to other multiplicative comparison situations using manipulatives such as cubes. For example, provide the student with two trains of cubes. The first train has four blue cubes and the second train has 20 cubes total (groups of four in alternating colors). Guide the student to compare in terms of multiplication and ask, “How do the lengths of the two trains compare? Ask the student to write a multiplication equation and to explain his or her reasoning.

Assist the student in making sense of the problem. Then provide similar problems and have the student use manipulatives to model the multiplicative comparison. Guide the student to write a multiplication equation that represents the model.

Consider using the MFAS task Dogs as Pets.

Moving Forward

The student struggles to solve multiplicative comparison problems.

The student is able to solve one of the multiplicative comparison problems yet struggles to solve the second.

The student may or may not write equations correctly.

The student solves one of the problems using addition (or subtraction) providing an incorrect response.

The student needs much prompting to solve the first problem, but is subsequently able to solve the second problem with little prompting.

If William had thrown the football twice as far, how far would it have gone?

If Abed had twice (or three times) as many cards, how many cards would he have?

Provide the student with additional multiplicative comparison word problems. Guide the student in making sense of the problems by first describing the action in the problems in his or her own words. Prompt the student to explain the relationship between the quantities in the problem.

Provide opportunities for the student to write equations that model word problems beginning with the unknown in the result. Then transition the student to writing equations to model multiplicative comparison situations in which the unknown is the number of times larger one quantity is than another.

Have the student solve multiplicative comparison word problems with an unknown product. Consider using the MFAS task Dogs As Pets.

Almost There

The student incorrectly writes the equation for one or both problems.

The student solves each problem correctly and explains his or her reasoning. However, he or she does not write an equation correctly, does not write an equation at all, or writes the equation vertically omitting the equal sign.

Why did you multiply by six? Was something six times larger?

What are we trying to find in this problem? What symbol should we use and where should it go in our equation?

What are we comparing? How can we write numbers to show that comparison?

Model for the student how to write equations that relate to the problems.

Provide opportunities for the student to write equations that model word problems beginning with the unknown in the result. Then transition the student to writing equations to model multiplicative comparison situations in which the unknown is the number of times larger one quantity is than another.

Consider using the MFAS task Writing An Equation to Match A Word Problem.

Got It

The student provides complete and correct responses to all components of the task.

The student solves each problem correctly and explains his or her reasoning. He or she writes either 6 x ___ = 18 or 18 ÷ 6 = ___ as the equation for the first problem and 5 x ___ = 20 or 20 ÷ 5 = ____ for the second problem.

   

Is there another equation that you could write to model this word problem?

How could you tell another student who was struggling with these types of problems how to solve them?

Challenge the student to write an additional equation that matches the word problem.

Have the student share his or her solution strategy and equation with the class.

Consider using the MFAS Task Books and Yarn.