← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 120 · 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 525 + 165? (a) 900 (b) 700 (c) 500
  2. 2.Best estimate of 543 + 580? (a) 900 (b) 1300 (c) 1100
  3. 3.Best estimate of 98 × 20? (a) 20000 (b) 2000 (c) 200
  4. 4.Best estimate of 19 × 42? (a) 8000 (b) 800 (c) 80
  5. 5.Best estimate of 66 × 66? (a) 4900 (b) 490 (c) 49000
  6. 6.Best estimate of 734 + 192? (a) 700 (b) 1100 (c) 900
  7. 7.Best estimate of 66 × 98? (a) 70000 (b) 7000 (c) 700
  8. 8.Best estimate of 78 × 39? (a) 3200 (b) 320 (c) 32000
  9. 9.Best estimate of 285 + 745? (a) 1000 (b) 1200 (c) 800
  10. 10.Best estimate of 82 × 59? (a) 480 (b) 4800 (c) 48000
  11. 11.Best estimate of 33 × 20? (a) 60 (b) 6000 (c) 600
  12. 12.Best estimate of 512 + 408? (a) 900 (b) 1100 (c) 700
  13. 13.Best estimate of 16 × 24? (a) 4000 (b) 40 (c) 400
  14. 14.Best estimate of 124 + 421? (a) 500 (b) 700 (c) 300
  15. 15.Best estimate of 28 × 70? (a) 2100 (b) 21000 (c) 210
  16. 16.Best estimate of 759 + 175? (a) 800 (b) 1200 (c) 1000
  17. 17.Best estimate of 218 + 553? (a) 600 (b) 800 (c) 1000
  18. 18.Best estimate of 291 + 179? (a) 700 (b) 300 (c) 500
  19. 19.Best estimate of 304 + 749? (a) 1200 (b) 1000 (c) 800
  20. 20.Best estimate of 96 × 42? (a) 4000 (b) 40000 (c) 400
  21. 21.Best estimate of 77 × 98? (a) 8000 (b) 80000 (c) 800
  22. 22.Best estimate of 147 + 792? (a) 900 (b) 1100 (c) 700
  23. 23.Best estimate of 454 + 629? (a) 1300 (b) 900 (c) 1100
  24. 24.Best estimate of 97 × 57? (a) 60000 (b) 600 (c) 6000
  25. 25.Best estimate of 77 × 27? (a) 2400 (b) 24000 (c) 240
  26. 26.Best estimate of 331 + 872? (a) 1000 (b) 1200 (c) 1400
  27. 27.Best estimate of 78 × 59? (a) 4800 (b) 48000 (c) 480
  28. 28.Best estimate of 604 + 304? (a) 900 (b) 1100 (c) 700
  29. 29.Best estimate of 52 × 12? (a) 5000 (b) 50 (c) 500
  30. 30.Best estimate of 500 + 170? (a) 700 (b) 500 (c) 900
  31. 31.Best estimate of 16 × 34? (a) 600 (b) 6000 (c) 60
  32. 32.Best estimate of 51 × 91? (a) 4500 (b) 450 (c) 45000
  33. 33.Best estimate of 23 × 63? (a) 1200 (b) 12000 (c) 120
  34. 34.Best estimate of 98 × 33? (a) 300 (b) 3000 (c) 30000
  35. 35.Best estimate of 74 × 52? (a) 35000 (b) 3500 (c) 350
  36. 36.Best estimate of 22 × 32? (a) 600 (b) 60 (c) 6000
  37. 37.Best estimate of 69 × 89? (a) 630 (b) 6300 (c) 63000
  38. 38.Best estimate of 79 × 56? (a) 480 (b) 4800 (c) 48000
  39. 39.Best estimate of 267 + 133? (a) 400 (b) 200 (c) 600
  40. 40.Best estimate of 590 + 618? (a) 1000 (b) 1200 (c) 1400

Answer key

  1. 700
  2. 1100
  3. 2000
  4. 800
  5. 4900
  6. 900
  7. 7000
  8. 3200
  9. 1000
  10. 4800
  11. 600
  12. 900
  13. 400
  14. 500
  15. 2100
  16. 1000
  17. 800
  18. 500
  19. 1000
  20. 4000
  21. 8000
  22. 900
  23. 1100
  24. 6000
  25. 2400
  26. 1200
  27. 4800
  28. 900
  29. 500
  30. 700
  31. 600
  32. 4500
  33. 1200
  34. 3000
  35. 3500
  36. 600
  37. 6300
  38. 4800
  39. 400
  40. 1200

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