## Subtraction and Addition Strategies

Students need a range of strategies to work efficiently with numbers. Mental computation strategies are an important building block in mathematics. The following worksheets provide students with opportunities to understand and practise strategies such as rainbow facts, doubles, count on and count back, and bridge to 10.

### Rainbow Facts Strategy

**Rainbow Facts** are number pairs that add to ten. For example: 4+6 and 8+2. **Near Rainbow Facts** are number pairs such as 7+4 or 5+6. Students can use their knowledge of Rainbow Facts to solve by adjusting up or down 1 as needed. A strong knowledge of these number combinations helps with faster calculation of more difficult number problems.

Rainbow Facts 10 Frame (Addition)
Use ten frames to learn rainbow facts. |
Rainbow Facts 10 Frame (Subtraction)
Use ten frames to learn rainbow facts. |
Rainbow Facts Worksheet
Complete addition and subtraction rainbow facts. |

Near Rainbow Facts Worksheet
Use knowledge of rainbow facts to help work out these addition and subtraction sums. |
Part Part Whole: Rainbow Facts
Complete the part-part-whole models . |
Game: 4 In a Row
Build fluency of rainbow facts the fun way! |

### Doubles Strategy

Having an immediate recall of doubles facts is very important. Doubles can also be used to aid with subtraction. For example: 14-7. **Near Doubles Facts** are number pairs such as 7+8 or 4+5. Students can use their knowledge of doubles to solve by adjusting up or down 1 as needed.

Doubles Strategy Worksheet
Complete doubles sums and practise halving numbers. |
Double Plus 1 Sheet
Learn to use doubles to solve other facts. |
‘Near Doubles’ Worksheet
Complete near doubles facts and extended near doubles sums. |

Game: Double It
Build fluency recalling Doubles Facts. |

### Count On/Count Back Strategy

Counting on is a very useful strategy when adding 1, 2 or 3 to a given number. Students must identify the larger number and count on to get the answer. Conversely, counting back is used when subtracting 1,2 or 3 from a given number.

Eg. 2 + 23… 24, **25**.

Counting On
Practice using a number line to count on from given numbers. |
Counting Back
Practice using a number line to count back from given numbers. |
Count On Worksheet
Solve the addition sums as quickly as possible using the ‘counting on’ strategy. |

Count Back Worksheet
Solve the subtraction sums as quickly as possible using the ‘counting back’ strategy. |
Number Line Addition Sheet 1
Solve simple addition sums using given number lines. |
Number Line Subtraction Sheet 1
Number Line Subtraction Sheet 2 Solve simple subtraction using given number lines. |

Counting and Adding
Count the objects to find the total. |
Counting, Adding & Writing
Count the objects and write the number sentence. |
Counting On Sheet
Count on from given numbers. |

Pirate Count On
Addition skills: Practice counting on. |
Pirate Addition
Add the pirate objects. |
Pirate Addition with Equations
Add the pirate objects and write the equation. |

### Bridge to 10 Strategy

When adding a number close to 10 (or 100, etc), it can be useful to add as if it were 10, and adjust the answer up or down as needed.

Bridge to Ten: Addition
Solve the sums as quickly as possible using the bride to ten strategy to help. |
Moving Around the Grid Sheet 1
Moving Around the Grid Sheet 2 Use knowledge of number to help work out which numbers belong in the shaded boxes (entire 100 grid). |
Grid Segments Sheet 1
Use knowledge of number to help work out which numbers belong in the shaded boxes (individual grid segments). |

### Combination of Strategies

Choose the best strategy to solve the addition and subtraction problems.

Strategies Worksheet
Learn and apply different mental computation strategies. Colour the sums according to the strategy used. |
Strategies Worksheet
Learn and apply different mental computation strategies. Line the sums up to the matching strategies. |

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