Lesson objective: Understand that a bundle of ten tens can be thought of as a hundred.

Students bring prior knowledge of place value to the tens place from Grade 1, Unit 8. This prior knowledge is extended to place value to the hundreds place as students bundle and count groups of ten and discover the equivalence to 100. A conceptual challenge students may encounter is understanding that three groups (for example) of ten is equivalent to 30 instead of equivalent to 3.

The concept is developed through work with base ten blocks and bundling straws, which helps students come to understand that when you make a group, it doesn't revert to a value of one, but it actually composes of the amount in the group.

This work helps students deepen their understanding of operations because it allows them to compose ten tens to equal 100.

Students engage in Mathematical Practice 4 (Model with mathematics) as they investigate bundling items into groups of ten, and then grouping ten of those tens to equal 100.

**Key vocabulary:**

- bundle
- digits
- equivalent
- group
- hundred
- tens

**Special materials needed:**

- base ten blocks
- rubber bands (for bundling)
- straws