← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 437 · 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 52 × 50? (a) 2500 (b) 250 (c) 25000
  2. 2.Best estimate of 485 + 458? (a) 1200 (b) 1000 (c) 800
  3. 3.Best estimate of 661 + 125? (a) 1000 (b) 600 (c) 800
  4. 4.Best estimate of 785 + 762? (a) 1400 (b) 1600 (c) 1800
  5. 5.Best estimate of 297 + 368? (a) 900 (b) 500 (c) 700
  6. 6.Best estimate of 251 + 543? (a) 1000 (b) 600 (c) 800
  7. 7.Best estimate of 73 × 26? (a) 210 (b) 21000 (c) 2100
  8. 8.Best estimate of 98 × 18? (a) 20000 (b) 2000 (c) 200
  9. 9.Best estimate of 440 + 687? (a) 900 (b) 1100 (c) 1300
  10. 10.Best estimate of 837 + 602? (a) 1400 (b) 1200 (c) 1600
  11. 11.Best estimate of 88 × 21? (a) 1800 (b) 18000 (c) 180
  12. 12.Best estimate of 182 + 461? (a) 700 (b) 500 (c) 900
  13. 13.Best estimate of 21 × 47? (a) 10000 (b) 100 (c) 1000
  14. 14.Best estimate of 195 + 144? (a) 500 (b) 300 (c) 100
  15. 15.Best estimate of 16 × 50? (a) 1000 (b) 100 (c) 10000
  16. 16.Best estimate of 17 × 40? (a) 80 (b) 8000 (c) 800
  17. 17.Best estimate of 88 × 16? (a) 180 (b) 1800 (c) 18000
  18. 18.Best estimate of 88 × 42? (a) 3600 (b) 360 (c) 36000
  19. 19.Best estimate of 39 × 20? (a) 8000 (b) 80 (c) 800
  20. 20.Best estimate of 451 + 556? (a) 1100 (b) 900 (c) 1300
  21. 21.Best estimate of 96 × 72? (a) 7000 (b) 700 (c) 70000
  22. 22.Best estimate of 32 × 96? (a) 30000 (b) 300 (c) 3000
  23. 23.Best estimate of 22 × 50? (a) 10000 (b) 100 (c) 1000
  24. 24.Best estimate of 662 + 699? (a) 1200 (b) 1600 (c) 1400
  25. 25.Best estimate of 334 + 188? (a) 300 (b) 500 (c) 700
  26. 26.Best estimate of 216 + 395? (a) 600 (b) 800 (c) 400
  27. 27.Best estimate of 51 × 61? (a) 3000 (b) 30000 (c) 300
  28. 28.Best estimate of 374 + 283? (a) 700 (b) 500 (c) 900
  29. 29.Best estimate of 32 × 89? (a) 2700 (b) 27000 (c) 270
  30. 30.Best estimate of 468 + 151? (a) 700 (b) 900 (c) 500
  31. 31.Best estimate of 56 × 21? (a) 1200 (b) 120 (c) 12000
  32. 32.Best estimate of 97 × 63? (a) 60000 (b) 6000 (c) 600
  33. 33.Best estimate of 291 + 593? (a) 900 (b) 1100 (c) 700
  34. 34.Best estimate of 13 × 18? (a) 2000 (b) 200 (c) 20
  35. 35.Best estimate of 26 × 56? (a) 18000 (b) 180 (c) 1800
  36. 36.Best estimate of 16 × 62? (a) 12000 (b) 1200 (c) 120
  37. 37.Best estimate of 304 + 370? (a) 700 (b) 900 (c) 500
  38. 38.Best estimate of 93 × 86? (a) 810 (b) 8100 (c) 81000
  39. 39.Best estimate of 763 + 601? (a) 1600 (b) 1400 (c) 1200
  40. 40.Best estimate of 26 × 71? (a) 2100 (b) 21000 (c) 210

Answer key

  1. 2500
  2. 1000
  3. 800
  4. 1600
  5. 700
  6. 800
  7. 2100
  8. 2000
  9. 1100
  10. 1400
  11. 1800
  12. 700
  13. 1000
  14. 300
  15. 1000
  16. 800
  17. 1800
  18. 3600
  19. 800
  20. 1100
  21. 7000
  22. 3000
  23. 1000
  24. 1400
  25. 500
  26. 600
  27. 3000
  28. 700
  29. 2700
  30. 700
  31. 1200
  32. 6000
  33. 900
  34. 200
  35. 1800
  36. 1200
  37. 700
  38. 8100
  39. 1400
  40. 2100

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