← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 485 · 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 331 + 724? (a) 1200 (b) 800 (c) 1000
  2. 2.Best estimate of 521 + 494? (a) 1200 (b) 1000 (c) 800
  3. 3.Best estimate of 42 × 52? (a) 2000 (b) 200 (c) 20000
  4. 4.Best estimate of 193 + 272? (a) 500 (b) 300 (c) 700
  5. 5.Best estimate of 60 × 36? (a) 24000 (b) 2400 (c) 240
  6. 6.Best estimate of 352 + 296? (a) 700 (b) 500 (c) 900
  7. 7.Best estimate of 33 × 78? (a) 2400 (b) 240 (c) 24000
  8. 8.Best estimate of 754 + 643? (a) 1400 (b) 1200 (c) 1600
  9. 9.Best estimate of 485 + 124? (a) 600 (b) 400 (c) 800
  10. 10.Best estimate of 542 + 471? (a) 800 (b) 1200 (c) 1000
  11. 11.Best estimate of 39 × 70? (a) 28000 (b) 2800 (c) 280
  12. 12.Best estimate of 814 + 439? (a) 1400 (b) 1000 (c) 1200
  13. 13.Best estimate of 31 × 40? (a) 1200 (b) 120 (c) 12000
  14. 14.Best estimate of 692 + 251? (a) 800 (b) 1200 (c) 1000
  15. 15.Best estimate of 21 × 61? (a) 12000 (b) 120 (c) 1200
  16. 16.Best estimate of 57 × 18? (a) 120 (b) 12000 (c) 1200
  17. 17.Best estimate of 717 + 768? (a) 1500 (b) 1300 (c) 1700
  18. 18.Best estimate of 90 × 71? (a) 63000 (b) 630 (c) 6300
  19. 19.Best estimate of 43 × 72? (a) 2800 (b) 28000 (c) 280
  20. 20.Best estimate of 821 + 851? (a) 1500 (b) 1700 (c) 1900
  21. 21.Best estimate of 79 × 84? (a) 6400 (b) 64000 (c) 640
  22. 22.Best estimate of 69 × 96? (a) 700 (b) 7000 (c) 70000
  23. 23.Best estimate of 616 + 474? (a) 1100 (b) 900 (c) 1300
  24. 24.Best estimate of 30 × 87? (a) 270 (b) 2700 (c) 27000
  25. 25.Best estimate of 18 × 16? (a) 400 (b) 40 (c) 4000
  26. 26.Best estimate of 487 + 658? (a) 1000 (b) 1200 (c) 1400
  27. 27.Best estimate of 89 × 44? (a) 360 (b) 3600 (c) 36000
  28. 28.Best estimate of 621 + 579? (a) 1200 (b) 1400 (c) 1000
  29. 29.Best estimate of 836 + 198? (a) 1000 (b) 1200 (c) 800
  30. 30.Best estimate of 32 × 94? (a) 2700 (b) 27000 (c) 270
  31. 31.Best estimate of 639 + 690? (a) 1300 (b) 1500 (c) 1100
  32. 32.Best estimate of 412 + 640? (a) 1000 (b) 800 (c) 1200
  33. 33.Best estimate of 66 × 33? (a) 2100 (b) 21000 (c) 210
  34. 34.Best estimate of 36 × 74? (a) 280 (b) 28000 (c) 2800
  35. 35.Best estimate of 77 × 41? (a) 32000 (b) 3200 (c) 320
  36. 36.Best estimate of 475 + 255? (a) 1000 (b) 800 (c) 600
  37. 37.Best estimate of 46 × 37? (a) 20000 (b) 200 (c) 2000
  38. 38.Best estimate of 76 × 32? (a) 24000 (b) 2400 (c) 240
  39. 39.Best estimate of 41 × 81? (a) 320 (b) 32000 (c) 3200
  40. 40.Best estimate of 77 × 47? (a) 40000 (b) 4000 (c) 400

Answer key

  1. 1000
  2. 1000
  3. 2000
  4. 500
  5. 2400
  6. 700
  7. 2400
  8. 1400
  9. 600
  10. 1000
  11. 2800
  12. 1200
  13. 1200
  14. 1000
  15. 1200
  16. 1200
  17. 1500
  18. 6300
  19. 2800
  20. 1700
  21. 6400
  22. 7000
  23. 1100
  24. 2700
  25. 400
  26. 1200
  27. 3600
  28. 1200
  29. 1000
  30. 2700
  31. 1300
  32. 1000
  33. 2100
  34. 2800
  35. 3200
  36. 800
  37. 2000
  38. 2400
  39. 3200
  40. 4000

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