← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 518 · 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 94 × 51? (a) 4500 (b) 45000 (c) 450
  2. 2.Best estimate of 36 × 24? (a) 80 (b) 8000 (c) 800
  3. 3.Best estimate of 307 + 588? (a) 700 (b) 1100 (c) 900
  4. 4.Best estimate of 440 + 253? (a) 900 (b) 700 (c) 500
  5. 5.Best estimate of 290 + 554? (a) 1100 (b) 900 (c) 700
  6. 6.Best estimate of 70 × 86? (a) 630 (b) 6300 (c) 63000
  7. 7.Best estimate of 697 + 278? (a) 800 (b) 1200 (c) 1000
  8. 8.Best estimate of 475 + 600? (a) 900 (b) 1300 (c) 1100
  9. 9.Best estimate of 274 + 510? (a) 600 (b) 1000 (c) 800
  10. 10.Best estimate of 571 + 311? (a) 900 (b) 700 (c) 1100
  11. 11.Best estimate of 83 × 13? (a) 80 (b) 800 (c) 8000
  12. 12.Best estimate of 668 + 769? (a) 1700 (b) 1300 (c) 1500
  13. 13.Best estimate of 46 × 26? (a) 1500 (b) 15000 (c) 150
  14. 14.Best estimate of 18 × 36? (a) 8000 (b) 800 (c) 80
  15. 15.Best estimate of 234 + 346? (a) 500 (b) 700 (c) 300
  16. 16.Best estimate of 793 + 462? (a) 1100 (b) 1500 (c) 1300
  17. 17.Best estimate of 20 × 19? (a) 400 (b) 40 (c) 4000
  18. 18.Best estimate of 26 × 47? (a) 150 (b) 15000 (c) 1500
  19. 19.Best estimate of 18 × 76? (a) 16000 (b) 160 (c) 1600
  20. 20.Best estimate of 286 + 818? (a) 1300 (b) 1100 (c) 900
  21. 21.Best estimate of 729 + 786? (a) 1700 (b) 1500 (c) 1300
  22. 22.Best estimate of 21 × 68? (a) 14000 (b) 140 (c) 1400
  23. 23.Best estimate of 74 × 56? (a) 4200 (b) 42000 (c) 420
  24. 24.Best estimate of 90 × 76? (a) 72000 (b) 720 (c) 7200
  25. 25.Best estimate of 651 + 499? (a) 1200 (b) 1400 (c) 1000
  26. 26.Best estimate of 680 + 487? (a) 1400 (b) 1200 (c) 1000
  27. 27.Best estimate of 394 + 758? (a) 1200 (b) 1400 (c) 1000
  28. 28.Best estimate of 520 + 120? (a) 800 (b) 400 (c) 600
  29. 29.Best estimate of 69 × 60? (a) 42000 (b) 4200 (c) 420
  30. 30.Best estimate of 88 × 82? (a) 7200 (b) 72000 (c) 720
  31. 31.Best estimate of 44 × 20? (a) 8000 (b) 800 (c) 80
  32. 32.Best estimate of 267 + 321? (a) 600 (b) 400 (c) 800
  33. 33.Best estimate of 42 × 98? (a) 400 (b) 40000 (c) 4000
  34. 34.Best estimate of 276 + 410? (a) 700 (b) 900 (c) 500
  35. 35.Best estimate of 18 × 91? (a) 1800 (b) 18000 (c) 180
  36. 36.Best estimate of 589 + 526? (a) 1100 (b) 900 (c) 1300
  37. 37.Best estimate of 423 + 351? (a) 600 (b) 800 (c) 1000
  38. 38.Best estimate of 26 × 16? (a) 600 (b) 60 (c) 6000
  39. 39.Best estimate of 682 + 302? (a) 800 (b) 1200 (c) 1000
  40. 40.Best estimate of 96 × 66? (a) 7000 (b) 700 (c) 70000

Answer key

  1. 4500
  2. 800
  3. 900
  4. 700
  5. 900
  6. 6300
  7. 1000
  8. 1100
  9. 800
  10. 900
  11. 800
  12. 1500
  13. 1500
  14. 800
  15. 500
  16. 1300
  17. 400
  18. 1500
  19. 1600
  20. 1100
  21. 1500
  22. 1400
  23. 4200
  24. 7200
  25. 1200
  26. 1200
  27. 1200
  28. 600
  29. 4200
  30. 7200
  31. 800
  32. 600
  33. 4000
  34. 700
  35. 1800
  36. 1100
  37. 800
  38. 600
  39. 1000
  40. 7000

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