Lesson objective: Practice creating equations by understanding number bonds.

This lesson helps to build procedural skill with whole number addition and subtraction. Number bonds are used here because they highlight the relationship between addition and subtraction. This work develops students' understanding that we can find unknown values in addition or subtraction situations using the relationship between addition and subtraction.

Students engage in Mathematical Practice 7 as they look closely to discern a pattern or structure. The idea of structure is essential in this task as students should notice that it is always true that the parts, when combined, equal the whole when representing addition and subtraction relationships using number bonds.

**Key vocabulary:**

- equation
- number bond
- part
- whole

**Special materials needed:**

- place value tools for concrete learners