Algebraic Thinking

balls, balls, balls

source: Elementary and Middle School Mathematics: Teaching Developmentally by John A. Van De Walle, Karen S. Karp, and Jennifer M. Bay-Williams. Activity 14.9

Materials:

• paper handouts or an alternate way to distribute ball facts
• paper/pencils for students to work with

Directions:

• students will figure out the weight of three balls, given the facts pictured on the right (baseball + football = 1.25 pounds, baseball + soccer ball = 1.35 pounds, soccer ball + football = 1.9 pounds)

• ask students to look at each fact and make observations that help them generate other facts
• example: noticing that the soccer ball weights .1 lb more than the football
• write facts like this the same way you wrote the other statements
• continue until you have solved the problem :)