When rounding to tens we look at which ten is closer.
If the number ends in 1, 2, 3 or 4, we round down.
If the number ends in 5, 6, 7, 8 or 9, we round up.
Example: 34 ≈ 30 (30 is closer than 40)
Example: 38 ≈ 40 (40 is closer than 30)
Example
- 30
- 40