Checkpoint: rounding and quick times

A school buys one notebook for each of 83 children. Notebooks come in packs of 10. How many notebooks should it buy?

• 80, because 83 is nearest to 80
• 90, because only whole packs can be bought
• 83, the exact count

Take 9,30,000 − 4,60,000. You want an estimate never more than the answer. How do you round?

• The first number up, the second down
• Both numbers down
• The first number down, the second up

What is 88 × 125 by the quick way?

• 22,000
• 44,000
• 11,000

Which pair do you multiply first in 8 × 19 × 125?

• 8 × 125
• 8 × 19
• 19 × 125