Rounding and Estimation Flashcards

Grade 3 · Math · Flashcards

Review rounding rules and estimation strategies with these handy flashcards.

Flashcards

Round to nearest ten: ones digit 0–4: Round down. Keep the tens digit the same. Example: 32 → 30
Round to nearest ten: ones digit 5–9: Round up. Add 1 to the tens digit. Example: 37 → 40
Round to nearest hundred: tens digit 0–4: Round down. Keep the hundreds digit the same. Example: 230 → 200
Round to nearest hundred: tens digit 5–9: Round up. Add 1 to the hundreds digit. Example: 270 → 300
Round 55 to the nearest ten: 60 (ones digit is 5, round up)
Round 192 to the nearest hundred: 200 (tens digit is 9, round up)
Round 845 to the nearest hundred: 800 (tens digit is 4, round down)
Round 98 to the nearest ten: 100 (ones digit is 8, round up from 90 to 100)
Estimate 78 + 43: 80 + 40 = 120 (exact: 121)
Estimate 91 - 47: 90 - 50 = 40 (exact: 44)
What does 'about how many' mean?: Use estimation — round numbers first, then calculate for a quick approximate answer.
Is an estimate exact?: No. An estimate is close but not exact. It helps you check if an answer is reasonable.