Using and explaining addition and subtraction strategies

Maths

1. Use the 'round and adjust' strategy to solve: 398 + 212.

2. Use the 'find the difference by adding on' strategy to complete the equation: 438 + _____ = 620.

3. Use the 'partitioning for subtraction' strategy to solve: 487 - 134 =

4. Use addition and subtraction to find the missing part of this equation: 124 + ______ + 330 = 754

5. Use addition and subtraction to find the missing part of this equation: 389 + ______ + 421 = 924

1. Complete the following equation using your knowledge of number bonds: 74 + _____ = 100

2. Use the partitioning strategy to solve the following equation: 34 + 13 =

A rule which helps us to add by using the column method at all times.

A rule which states that addition and subtraction are the opposite of each other.

A rule which states that you can swap the numbers in an addition/multiplication equation and your answer will remain the same.

A rule which suggests that we should always check our answers using the inverse method.

4. Use the round and adjust strategy to solve: 71 + 16 =

5. Which strategy would be most appropriate/efficient when solving: 33 + 21 =