← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 23 · 40 questions
TalentJR

How to do it in your head (Round, then work): Round each number: 2-digit numbers to the nearest ten, 3-digit numbers to the nearest hundred. Do the easy sum with the round numbers. Choose the option closest to your estimate.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 36 × 22? (a) 800 (b) 8000 (c) 80
  2. 2.Best estimate of 719 + 165? (a) 700 (b) 1100 (c) 900
  3. 3.Best estimate of 513 + 194? (a) 700 (b) 500 (c) 900
  4. 4.Best estimate of 385 + 833? (a) 1200 (b) 1400 (c) 1000
  5. 5.Best estimate of 265 + 335? (a) 600 (b) 800 (c) 400
  6. 6.Best estimate of 93 × 62? (a) 54000 (b) 5400 (c) 540
  7. 7.Best estimate of 32 × 82? (a) 2400 (b) 24000 (c) 240
  8. 8.Best estimate of 390 + 240? (a) 800 (b) 400 (c) 600
  9. 9.Best estimate of 40 × 97? (a) 4000 (b) 400 (c) 40000
  10. 10.Best estimate of 76 × 42? (a) 32000 (b) 3200 (c) 320
  11. 11.Best estimate of 76 × 70? (a) 5600 (b) 56000 (c) 560
  12. 12.Best estimate of 451 + 675? (a) 1000 (b) 1400 (c) 1200
  13. 13.Best estimate of 242 + 136? (a) 500 (b) 300 (c) 100
  14. 14.Best estimate of 32 × 21? (a) 60 (b) 6000 (c) 600
  15. 15.Best estimate of 96 × 82? (a) 80000 (b) 800 (c) 8000
  16. 16.Best estimate of 857 + 261? (a) 1200 (b) 1000 (c) 1400
  17. 17.Best estimate of 43 × 52? (a) 2000 (b) 20000 (c) 200
  18. 18.Best estimate of 57 × 16? (a) 1200 (b) 12000 (c) 120
  19. 19.Best estimate of 98 × 19? (a) 20000 (b) 2000 (c) 200
  20. 20.Best estimate of 265 + 694? (a) 1000 (b) 800 (c) 1200
  21. 21.Best estimate of 258 + 688? (a) 800 (b) 1200 (c) 1000
  22. 22.Best estimate of 83 × 24? (a) 160 (b) 16000 (c) 1600
  23. 23.Best estimate of 582 + 492? (a) 1100 (b) 900 (c) 1300
  24. 24.Best estimate of 129 + 837? (a) 1100 (b) 700 (c) 900
  25. 25.Best estimate of 26 × 79? (a) 240 (b) 2400 (c) 24000
  26. 26.Best estimate of 74 × 47? (a) 3500 (b) 35000 (c) 350
  27. 27.Best estimate of 816 + 410? (a) 1000 (b) 1200 (c) 1400
  28. 28.Best estimate of 22 × 12? (a) 20 (b) 200 (c) 2000
  29. 29.Best estimate of 366 + 245? (a) 600 (b) 400 (c) 800
  30. 30.Best estimate of 98 × 81? (a) 8000 (b) 800 (c) 80000
  31. 31.Best estimate of 84 × 48? (a) 40000 (b) 4000 (c) 400
  32. 32.Best estimate of 79 × 33? (a) 24000 (b) 2400 (c) 240
  33. 33.Best estimate of 66 × 24? (a) 140 (b) 14000 (c) 1400
  34. 34.Best estimate of 516 + 199? (a) 500 (b) 700 (c) 900
  35. 35.Best estimate of 197 + 604? (a) 800 (b) 600 (c) 1000
  36. 36.Best estimate of 670 + 214? (a) 900 (b) 700 (c) 1100
  37. 37.Best estimate of 152 + 264? (a) 300 (b) 700 (c) 500
  38. 38.Best estimate of 485 + 704? (a) 1200 (b) 1000 (c) 1400
  39. 39.Best estimate of 52 × 89? (a) 45000 (b) 4500 (c) 450
  40. 40.Best estimate of 66 × 79? (a) 5600 (b) 56000 (c) 560

Answer key

  1. 800
  2. 900
  3. 700
  4. 1200
  5. 600
  6. 5400
  7. 2400
  8. 600
  9. 4000
  10. 3200
  11. 5600
  12. 1200
  13. 300
  14. 600
  15. 8000
  16. 1200
  17. 2000
  18. 1200
  19. 2000
  20. 1000
  21. 1000
  22. 1600
  23. 1100
  24. 900
  25. 2400
  26. 3500
  27. 1200
  28. 200
  29. 600
  30. 8000
  31. 4000
  32. 2400
  33. 1400
  34. 700
  35. 800
  36. 900
  37. 500
  38. 1200
  39. 4500
  40. 5600

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths