← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 698 · 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 436 + 158? (a) 600 (b) 800 (c) 400
  2. 2.Best estimate of 389 + 610? (a) 800 (b) 1000 (c) 1200
  3. 3.Best estimate of 57 × 18? (a) 120 (b) 12000 (c) 1200
  4. 4.Best estimate of 270 + 614? (a) 900 (b) 1100 (c) 700
  5. 5.Best estimate of 81 × 41? (a) 320 (b) 32000 (c) 3200
  6. 6.Best estimate of 834 + 485? (a) 1100 (b) 1500 (c) 1300
  7. 7.Best estimate of 236 + 835? (a) 1000 (b) 1200 (c) 800
  8. 8.Best estimate of 188 + 565? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 41 × 20? (a) 80 (b) 8000 (c) 800
  10. 10.Best estimate of 71 × 67? (a) 49000 (b) 4900 (c) 490
  11. 11.Best estimate of 257 + 742? (a) 1200 (b) 1000 (c) 800
  12. 12.Best estimate of 12 × 40? (a) 4000 (b) 400 (c) 40
  13. 13.Best estimate of 58 × 77? (a) 48000 (b) 4800 (c) 480
  14. 14.Best estimate of 87 × 13? (a) 900 (b) 9000 (c) 90
  15. 15.Best estimate of 71 × 48? (a) 3500 (b) 35000 (c) 350
  16. 16.Best estimate of 209 + 518? (a) 500 (b) 700 (c) 900
  17. 17.Best estimate of 710 + 126? (a) 1000 (b) 600 (c) 800
  18. 18.Best estimate of 610 + 806? (a) 1400 (b) 1200 (c) 1600
  19. 19.Best estimate of 776 + 413? (a) 1000 (b) 1400 (c) 1200
  20. 20.Best estimate of 130 + 574? (a) 500 (b) 700 (c) 900
  21. 21.Best estimate of 44 × 41? (a) 16000 (b) 160 (c) 1600
  22. 22.Best estimate of 431 + 297? (a) 700 (b) 900 (c) 500
  23. 23.Best estimate of 14 × 37? (a) 400 (b) 4000 (c) 40
  24. 24.Best estimate of 91 × 79? (a) 7200 (b) 72000 (c) 720
  25. 25.Best estimate of 201 + 614? (a) 1000 (b) 800 (c) 600
  26. 26.Best estimate of 286 + 724? (a) 1000 (b) 800 (c) 1200
  27. 27.Best estimate of 326 + 494? (a) 800 (b) 600 (c) 1000
  28. 28.Best estimate of 84 × 81? (a) 640 (b) 64000 (c) 6400
  29. 29.Best estimate of 493 + 869? (a) 1400 (b) 1200 (c) 1600
  30. 30.Best estimate of 26 × 47? (a) 150 (b) 15000 (c) 1500
  31. 31.Best estimate of 579 + 627? (a) 1400 (b) 1200 (c) 1000
  32. 32.Best estimate of 73 × 80? (a) 5600 (b) 560 (c) 56000
  33. 33.Best estimate of 252 + 218? (a) 700 (b) 500 (c) 300
  34. 34.Best estimate of 97 × 12? (a) 10000 (b) 1000 (c) 100
  35. 35.Best estimate of 355 + 173? (a) 400 (b) 800 (c) 600
  36. 36.Best estimate of 44 × 73? (a) 28000 (b) 2800 (c) 280
  37. 37.Best estimate of 46 × 31? (a) 1500 (b) 15000 (c) 150
  38. 38.Best estimate of 153 + 636? (a) 600 (b) 800 (c) 1000
  39. 39.Best estimate of 76 × 37? (a) 32000 (b) 3200 (c) 320
  40. 40.Best estimate of 41 × 56? (a) 2400 (b) 24000 (c) 240

Answer key

  1. 600
  2. 1000
  3. 1200
  4. 900
  5. 3200
  6. 1300
  7. 1000
  8. 800
  9. 800
  10. 4900
  11. 1000
  12. 400
  13. 4800
  14. 900
  15. 3500
  16. 700
  17. 800
  18. 1400
  19. 1200
  20. 700
  21. 1600
  22. 700
  23. 400
  24. 7200
  25. 800
  26. 1000
  27. 800
  28. 6400
  29. 1400
  30. 1500
  31. 1200
  32. 5600
  33. 500
  34. 1000
  35. 600
  36. 2800
  37. 1500
  38. 800
  39. 3200
  40. 2400

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