Lesson objective: Students will be able to fluently add ten to a 2-digit number.

This lesson helps to build fluency with adding 10. Cubes and hundred charts are used here because students can access a concrete or abstract representation. This work develops students' understanding that 10 can be added to any two-digit number without having to count on.

Students engage in Mathematical Practice 5: Use Appropriate Tools Strategically as they choose their preferred tool (cubes or hundred charts) to practice adding 10 fluently.

**Key vocabulary:**

- add
- more
- ones' place
- place value
- tens' place

**Special materials needed:**

- cubes (towers of 10 cubes and loose cubes)
- hundred charts (1 per pair of students)
- number cards (1 set per pair of students)
- recording sheets (1 per student)