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MA19.2.2
Fluently add and subtract within 20 using mental strategies such as counting on, making ten, decomposing a number leading to ten, using the relationship between addition and subtraction, and creating equivalent but easier or known sums.

Fluently add and subtract within 20 using mental strategies such as counting on, making ten, decomposing a number leading to ten, using the relationship between addition and subtraction, and creating equivalent but easier or known sums.

### Unpacked Content

## UP:MA19.2.2

### Vocabulary

- Fluently

### Knowledge

- how to use mental strategies to add and subtract within 20.

### Skills

- use addition and subtraction strategies efficiently.

### Understanding

- fluency involves a mixture of "just knowing" answers, knowing answers from patterns, and knowing answers from the use of strategies. The word fluently is used in the standards to mean accurately, efficiently, and flexibly.