# 1.3 Adding and Subtracting Within 20

## Unit Goals

- Students add and subtract within 20. Students apply the properties of operations and the relationship between addition and subtraction.

### Section A Goals

- Build toward fluency with adding and subtracting within 10.

### Section B Goals

- Add and subtract one-digit numbers from teen numbers without composing or decomposing a ten.
- Find the value that makes an addition or subtraction equation true, involving 10.
- Understand 10 ones as a ten and the numbers 11 to 19 as a ten and some ones.

### Section C Goals

- Add within 20, including three addends.

### Section D Goals

- Subtract within 20.