Problem Solving: Working Backwards

Monkey Business

NCTM published a similar problem several years ago.  The Monkey Business problem was created to help students practice the strategy of Working Backwards.  Review an earlier Mathwire Blog post on an easy Working Backwards strategy that uses circles and arrows to create a path forward and then reverses the operations to create a backwards path.

Monkey Business may be solved using this arrow path approach or using forward and backward tables as shown in the possible solution included with the Monkey Business handout.  No matter which method students use, the problem challenges them to think about mathematical operations very conceptually and use inverse operations to reverse the path. 

• Download the Monkey Business problem and solution.

The NCTM Illuminations website hosts a lesson plan for two similar problems, Mangoes and Sailors and Coconuts, the one on which Monkey Business is based.  Be sure to check out the site to dowload the problems and read through an alternate problem solving strategy.  Students will benefit from adding these different problem solving strategies to their repertoire for future use.

• Check out the NCTM Illuminations lesson designed for middle grade math students.