# Model and apply the associative property of addition to aid mental computation, eg 2 + 3 + 8 = 2 + 8 + 3 = 10 + 3 = 13

1. | Back to School: 5c + 15c + 7 c | |

2. | Add these 3 numbers: 8 + 3 + 2 | |

3. | Add these 3 numbers: 9 + 1 + 6 | |

4. | Add three numbers: 10 + 12 + 8 | |

5. | Add three numbers: 13 + 9 + 7 |