Lesson objective: Solve subtraction problems with multiples of ten by using a strategy.

This lesson helps to build fluency with subtraction problems using multiples of ten. Base ten blocks and an open number line are used here because they support students in subtracting groups of ten. This work develops students' understanding that we can use our understanding of place value to add and subtract multiples of ten.

Students engage in Mathematical Practice 6 (Attend to Precision) as they correctly solve equations and check they have Bingo.

**Key vocabulary:**

- base ten blocks
- known facts
- open number line
- subtraction

**Special materials needed:**

- base ten blocks (optional)
- bingo game board for each student
- blank number lines (optional)
- cards with multiples of ten subtraction equations
- chips or cubes to cover used spaces