Adding and subtracting using the 'round and adjust' strategy

Maths

Problem solving with integer addition and subtraction

The strategy involves rounding numbers to get an approximate answer.

The strategy involves rounding part of an equation to the nearest multiple of 10, 100, 1000, 10 000 or 100 000. Then, adjust for this rounding afterwards.

The strategy involves using partitioning to add and subtract.

The strategy involves using the column method to add and subtract.

2. Use 'rounding and adjusting' to solve: 53 700 + 3998 =

3. Use 'rounding and adjusting' to solve: 6880 - 2990 =

4. Use 'rounding and adjusting' to solve: 17 456 + 1980 =

5. Use 'rounding and adjusting' to solve: 215 678 + 3800 =

1. Use the derived fact '9-6 = 3' to solve 90 000 - 60 000 = ________.

2. Use the make 10 strategy to solve: 160 000 + 60 000 = _________.

3. Use either the derived facts or make 10 strategy to solve: 18 000 - 15 000 =

150 365 people attend an event. 80 000 people leave early. How many people are left?

Which derived fact could help us solve: 14 000 - 9000?

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Adding and subtracting using the 'round and adjust' strategy

Lesson outcome