← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 620 · 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 322 + 567? (a) 900 (b) 1100 (c) 700
  2. 2.Best estimate of 552 + 833? (a) 1200 (b) 1400 (c) 1600
  3. 3.Best estimate of 234 + 616? (a) 800 (b) 1000 (c) 600
  4. 4.Best estimate of 399 + 718? (a) 1100 (b) 900 (c) 1300
  5. 5.Best estimate of 90 × 63? (a) 5400 (b) 54000 (c) 540
  6. 6.Best estimate of 306 + 534? (a) 1000 (b) 800 (c) 600
  7. 7.Best estimate of 86 × 90? (a) 81000 (b) 810 (c) 8100
  8. 8.Best estimate of 131 + 699? (a) 800 (b) 1000 (c) 600
  9. 9.Best estimate of 17 × 49? (a) 100 (b) 1000 (c) 10000
  10. 10.Best estimate of 33 × 18? (a) 6000 (b) 60 (c) 600
  11. 11.Best estimate of 57 × 57? (a) 360 (b) 36000 (c) 3600
  12. 12.Best estimate of 96 × 29? (a) 3000 (b) 300 (c) 30000
  13. 13.Best estimate of 30 × 24? (a) 6000 (b) 600 (c) 60
  14. 14.Best estimate of 63 × 78? (a) 4800 (b) 48000 (c) 480
  15. 15.Best estimate of 669 + 660? (a) 1600 (b) 1400 (c) 1200
  16. 16.Best estimate of 18 × 46? (a) 1000 (b) 10000 (c) 100
  17. 17.Best estimate of 23 × 81? (a) 160 (b) 1600 (c) 16000
  18. 18.Best estimate of 340 + 510? (a) 1000 (b) 600 (c) 800
  19. 19.Best estimate of 739 + 264? (a) 1000 (b) 1200 (c) 800
  20. 20.Best estimate of 602 + 147? (a) 700 (b) 500 (c) 900
  21. 21.Best estimate of 685 + 820? (a) 1300 (b) 1500 (c) 1700
  22. 22.Best estimate of 559 + 586? (a) 1400 (b) 1000 (c) 1200
  23. 23.Best estimate of 125 + 136? (a) 400 (b) 200 (c) 0
  24. 24.Best estimate of 21 × 20? (a) 4000 (b) 40 (c) 400
  25. 25.Best estimate of 79 × 38? (a) 320 (b) 32000 (c) 3200
  26. 26.Best estimate of 474 + 157? (a) 500 (b) 700 (c) 900
  27. 27.Best estimate of 59 × 86? (a) 5400 (b) 54000 (c) 540
  28. 28.Best estimate of 755 + 339? (a) 900 (b) 1100 (c) 1300
  29. 29.Best estimate of 66 × 68? (a) 4900 (b) 49000 (c) 490
  30. 30.Best estimate of 425 + 502? (a) 1100 (b) 700 (c) 900
  31. 31.Best estimate of 22 × 46? (a) 10000 (b) 1000 (c) 100
  32. 32.Best estimate of 90 × 94? (a) 81000 (b) 810 (c) 8100
  33. 33.Best estimate of 384 + 834? (a) 1000 (b) 1200 (c) 1400
  34. 34.Best estimate of 313 + 756? (a) 1100 (b) 900 (c) 1300
  35. 35.Best estimate of 262 + 518? (a) 1000 (b) 600 (c) 800
  36. 36.Best estimate of 686 + 851? (a) 1400 (b) 1800 (c) 1600
  37. 37.Best estimate of 68 × 68? (a) 49000 (b) 4900 (c) 490
  38. 38.Best estimate of 828 + 309? (a) 1300 (b) 1100 (c) 900
  39. 39.Best estimate of 82 × 96? (a) 80000 (b) 8000 (c) 800
  40. 40.Best estimate of 34 × 16? (a) 600 (b) 60 (c) 6000

Answer key

  1. 900
  2. 1400
  3. 800
  4. 1100
  5. 5400
  6. 800
  7. 8100
  8. 800
  9. 1000
  10. 600
  11. 3600
  12. 3000
  13. 600
  14. 4800
  15. 1400
  16. 1000
  17. 1600
  18. 800
  19. 1000
  20. 700
  21. 1500
  22. 1200
  23. 200
  24. 400
  25. 3200
  26. 700
  27. 5400
  28. 1100
  29. 4900
  30. 900
  31. 1000
  32. 8100
  33. 1200
  34. 1100
  35. 800
  36. 1600
  37. 4900
  38. 1100
  39. 8000
  40. 600

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