Mental arithmetic
This practice focuses on choosing a helpful strategy before calculating, not on doing every step the long way.
How to solve this
- For addition, combine friendly parts: 340 + 280 can be 300 + 200 and 40 + 80.
- For subtraction, compensation often helps: 900 − 470 is the same as 930 − 500.
- For multiplication and division with round numbers, remove the zeroes carefully, calculate the core fact, then restore the place value.
Examples
340 + 280
620
900 - 470
430
4800 ÷ 60
80