← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 922 · 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 83 × 37? (a) 32000 (b) 3200 (c) 320
  2. 2.Best estimate of 774 + 713? (a) 1700 (b) 1300 (c) 1500
  3. 3.Best estimate of 78 × 24? (a) 16000 (b) 1600 (c) 160
  4. 4.Best estimate of 98 × 18? (a) 2000 (b) 20000 (c) 200
  5. 5.Best estimate of 329 + 836? (a) 1100 (b) 900 (c) 1300
  6. 6.Best estimate of 786 + 477? (a) 1100 (b) 1300 (c) 1500
  7. 7.Best estimate of 20 × 53? (a) 100 (b) 1000 (c) 10000
  8. 8.Best estimate of 59 × 29? (a) 180 (b) 1800 (c) 18000
  9. 9.Best estimate of 336 + 753? (a) 900 (b) 1300 (c) 1100
  10. 10.Best estimate of 591 + 503? (a) 1100 (b) 1300 (c) 900
  11. 11.Best estimate of 212 + 383? (a) 400 (b) 600 (c) 800
  12. 12.Best estimate of 170 + 199? (a) 400 (b) 200 (c) 600
  13. 13.Best estimate of 50 × 14? (a) 500 (b) 5000 (c) 50
  14. 14.Best estimate of 74 × 44? (a) 2800 (b) 28000 (c) 280
  15. 15.Best estimate of 29 × 57? (a) 18000 (b) 1800 (c) 180
  16. 16.Best estimate of 520 + 779? (a) 1100 (b) 1300 (c) 1500
  17. 17.Best estimate of 496 + 617? (a) 1300 (b) 1100 (c) 900
  18. 18.Best estimate of 497 + 435? (a) 1100 (b) 700 (c) 900
  19. 19.Best estimate of 67 × 72? (a) 49000 (b) 490 (c) 4900
  20. 20.Best estimate of 868 + 470? (a) 1200 (b) 1400 (c) 1600
  21. 21.Best estimate of 685 + 183? (a) 900 (b) 1100 (c) 700
  22. 22.Best estimate of 93 × 36? (a) 36000 (b) 3600 (c) 360
  23. 23.Best estimate of 67 × 87? (a) 63000 (b) 6300 (c) 630
  24. 24.Best estimate of 345 + 754? (a) 900 (b) 1100 (c) 1300
  25. 25.Best estimate of 48 × 77? (a) 40000 (b) 400 (c) 4000
  26. 26.Best estimate of 89 × 78? (a) 7200 (b) 720 (c) 72000
  27. 27.Best estimate of 715 + 136? (a) 800 (b) 1000 (c) 600
  28. 28.Best estimate of 237 + 174? (a) 600 (b) 200 (c) 400
  29. 29.Best estimate of 18 × 58? (a) 12000 (b) 1200 (c) 120
  30. 30.Best estimate of 78 × 84? (a) 64000 (b) 640 (c) 6400
  31. 31.Best estimate of 479 + 191? (a) 700 (b) 900 (c) 500
  32. 32.Best estimate of 867 + 618? (a) 1700 (b) 1300 (c) 1500
  33. 33.Best estimate of 56 × 26? (a) 18000 (b) 180 (c) 1800
  34. 34.Best estimate of 27 × 62? (a) 1800 (b) 180 (c) 18000
  35. 35.Best estimate of 23 × 26? (a) 600 (b) 60 (c) 6000
  36. 36.Best estimate of 91 × 62? (a) 540 (b) 54000 (c) 5400
  37. 37.Best estimate of 18 × 31? (a) 600 (b) 6000 (c) 60
  38. 38.Best estimate of 686 + 318? (a) 800 (b) 1200 (c) 1000
  39. 39.Best estimate of 93 × 12? (a) 9000 (b) 900 (c) 90
  40. 40.Best estimate of 655 + 597? (a) 1500 (b) 1300 (c) 1100

Answer key

  1. 3200
  2. 1500
  3. 1600
  4. 2000
  5. 1100
  6. 1300
  7. 1000
  8. 1800
  9. 1100
  10. 1100
  11. 600
  12. 400
  13. 500
  14. 2800
  15. 1800
  16. 1300
  17. 1100
  18. 900
  19. 4900
  20. 1400
  21. 900
  22. 3600
  23. 6300
  24. 1100
  25. 4000
  26. 7200
  27. 800
  28. 400
  29. 1200
  30. 6400
  31. 700
  32. 1500
  33. 1800
  34. 1800
  35. 600
  36. 5400
  37. 600
  38. 1000
  39. 900
  40. 1300

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