*Make sure all of the beads are in the ‘start position’. ‘White to Right’

# Let’s solve a problem using an authentic experience!

In the city there are many double decker buses. There are 10 seats on the upper deck and 10 seats on the lower deck. There are 8 passengers on the upper deck and 7 passengers on the lower deck. How many passengers are on the bus? Using the MathRack move 8 beads to the left on the upper ‘deck’ and 7 beads to the left on the lower ‘deck’. What do you see? As your students discuss what they are seeing and how many there are you will witness that there are many ways to see the problem 8 + 7. The structure of the MathRack encourages students to think flexibly by using relationships—subitizing, plus 1-2/minus 1-2, benchmarks 5 and 10, and part-part whole.

- Some ways to see 8 + 7 = 15
- 5 + 5 + 3 + 2
- 10 + 3 + 2
- 10 + 5
- 7 + 7 + 1
- 8 + 8 - 1
- 20 - 5