Grandpa's taking all the grandkids to the neatest amusement park ever: Safari Park. All the Jungle King rides cost 4 tickets. Rhino Rides are just two tickets. Monkey Games and Tiger Treats are a bargain at one ticket each. But a ride on the "spectacular, amazing, heart-pounding Terrible Tarantula" costs six tickets! Each of the kids has 20 tickets and has to figure out the best combination to have the most fun. Which would you choose?
An essential part of early algebraic thinking is understanding a "number sentence" with a missing element (8 + ? = 20), and the process for figuring out the unknown.
Illustrated by Steve Björkman.
Before reading the story, give your child (or each of your students) 20 pieces of paper to use as tickets. Work with them to solve each number sentence, solving for the unknown using the tickets to help work out the problem.
Look at the large sign showing all the rides and the number of tickets needed for each. Ask your child (or students) to think of several different ways to use the 20 tickets. Write a number sentence for each one. Do the same thing using 15 tickets, 18 tickets, or 10 tickets.
Think of a number and offer a clue such as "8 plus this number equals 12." When your child (or one of your students) figures out the answer, he gets to think up a number and offer a clue for the next round.