← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 232 · 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 52 × 26? (a) 150 (b) 15000 (c) 1500
  2. 2.Best estimate of 91 × 80? (a) 7200 (b) 72000 (c) 720
  3. 3.Best estimate of 764 + 442? (a) 1400 (b) 1000 (c) 1200
  4. 4.Best estimate of 86 × 86? (a) 8100 (b) 81000 (c) 810
  5. 5.Best estimate of 12 × 84? (a) 800 (b) 8000 (c) 80
  6. 6.Best estimate of 463 + 364? (a) 1100 (b) 900 (c) 700
  7. 7.Best estimate of 41 × 66? (a) 2800 (b) 28000 (c) 280
  8. 8.Best estimate of 69 × 87? (a) 6300 (b) 63000 (c) 630
  9. 9.Best estimate of 272 + 304? (a) 600 (b) 400 (c) 800
  10. 10.Best estimate of 27 × 38? (a) 120 (b) 1200 (c) 12000
  11. 11.Best estimate of 716 + 195? (a) 700 (b) 1100 (c) 900
  12. 12.Best estimate of 22 × 56? (a) 12000 (b) 120 (c) 1200
  13. 13.Best estimate of 24 × 28? (a) 6000 (b) 600 (c) 60
  14. 14.Best estimate of 79 × 63? (a) 4800 (b) 48000 (c) 480
  15. 15.Best estimate of 321 + 617? (a) 700 (b) 900 (c) 1100
  16. 16.Best estimate of 455 + 303? (a) 600 (b) 800 (c) 1000
  17. 17.Best estimate of 34 × 42? (a) 1200 (b) 12000 (c) 120
  18. 18.Best estimate of 36 × 74? (a) 28000 (b) 2800 (c) 280
  19. 19.Best estimate of 506 + 298? (a) 1000 (b) 800 (c) 600
  20. 20.Best estimate of 60 × 96? (a) 600 (b) 6000 (c) 60000
  21. 21.Best estimate of 17 × 81? (a) 16000 (b) 1600 (c) 160
  22. 22.Best estimate of 22 × 88? (a) 180 (b) 18000 (c) 1800
  23. 23.Best estimate of 215 + 379? (a) 800 (b) 400 (c) 600
  24. 24.Best estimate of 814 + 436? (a) 1200 (b) 1400 (c) 1000
  25. 25.Best estimate of 792 + 294? (a) 900 (b) 1100 (c) 1300
  26. 26.Best estimate of 47 × 73? (a) 350 (b) 35000 (c) 3500
  27. 27.Best estimate of 36 × 23? (a) 800 (b) 8000 (c) 80
  28. 28.Best estimate of 36 × 40? (a) 1600 (b) 16000 (c) 160
  29. 29.Best estimate of 86 × 87? (a) 810 (b) 8100 (c) 81000
  30. 30.Best estimate of 390 + 378? (a) 800 (b) 1000 (c) 600
  31. 31.Best estimate of 201 + 138? (a) 500 (b) 300 (c) 100
  32. 32.Best estimate of 59 × 42? (a) 24000 (b) 2400 (c) 240
  33. 33.Best estimate of 41 × 33? (a) 12000 (b) 120 (c) 1200
  34. 34.Best estimate of 616 + 500? (a) 900 (b) 1300 (c) 1100
  35. 35.Best estimate of 540 + 790? (a) 1100 (b) 1300 (c) 1500
  36. 36.Best estimate of 827 + 730? (a) 1300 (b) 1500 (c) 1700
  37. 37.Best estimate of 32 × 16? (a) 600 (b) 60 (c) 6000
  38. 38.Best estimate of 51 × 59? (a) 30000 (b) 3000 (c) 300
  39. 39.Best estimate of 21 × 86? (a) 18000 (b) 180 (c) 1800
  40. 40.Best estimate of 161 + 545? (a) 700 (b) 500 (c) 900

Answer key

  1. 1500
  2. 7200
  3. 1200
  4. 8100
  5. 800
  6. 900
  7. 2800
  8. 6300
  9. 600
  10. 1200
  11. 900
  12. 1200
  13. 600
  14. 4800
  15. 900
  16. 800
  17. 1200
  18. 2800
  19. 800
  20. 6000
  21. 1600
  22. 1800
  23. 600
  24. 1200
  25. 1100
  26. 3500
  27. 800
  28. 1600
  29. 8100
  30. 800
  31. 300
  32. 2400
  33. 1200
  34. 1100
  35. 1300
  36. 1500
  37. 600
  38. 3000
  39. 1800
  40. 700

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