← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 323 · 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 673 + 775? (a) 1500 (b) 1700 (c) 1300
  2. 2.Best estimate of 20 × 70? (a) 1400 (b) 14000 (c) 140
  3. 3.Best estimate of 40 × 47? (a) 20000 (b) 2000 (c) 200
  4. 4.Best estimate of 92 × 24? (a) 1800 (b) 180 (c) 18000
  5. 5.Best estimate of 30 × 23? (a) 60 (b) 600 (c) 6000
  6. 6.Best estimate of 84 × 78? (a) 64000 (b) 640 (c) 6400
  7. 7.Best estimate of 94 × 52? (a) 4500 (b) 450 (c) 45000
  8. 8.Best estimate of 807 + 346? (a) 1300 (b) 1100 (c) 900
  9. 9.Best estimate of 58 × 19? (a) 1200 (b) 12000 (c) 120
  10. 10.Best estimate of 398 + 162? (a) 600 (b) 800 (c) 400
  11. 11.Best estimate of 414 + 121? (a) 700 (b) 300 (c) 500
  12. 12.Best estimate of 84 × 20? (a) 160 (b) 1600 (c) 16000
  13. 13.Best estimate of 287 + 297? (a) 600 (b) 800 (c) 400
  14. 14.Best estimate of 836 + 625? (a) 1600 (b) 1200 (c) 1400
  15. 15.Best estimate of 23 × 13? (a) 2000 (b) 200 (c) 20
  16. 16.Best estimate of 378 + 645? (a) 1200 (b) 1000 (c) 800
  17. 17.Best estimate of 367 + 575? (a) 800 (b) 1200 (c) 1000
  18. 18.Best estimate of 669 + 151? (a) 900 (b) 1100 (c) 700
  19. 19.Best estimate of 69 × 98? (a) 70000 (b) 700 (c) 7000
  20. 20.Best estimate of 391 + 128? (a) 500 (b) 700 (c) 300
  21. 21.Best estimate of 251 + 536? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 120 + 126? (a) 400 (b) 200 (c) 0
  23. 23.Best estimate of 60 × 82? (a) 48000 (b) 4800 (c) 480
  24. 24.Best estimate of 29 × 17? (a) 60 (b) 6000 (c) 600
  25. 25.Best estimate of 448 + 385? (a) 600 (b) 1000 (c) 800
  26. 26.Best estimate of 49 × 18? (a) 1000 (b) 10000 (c) 100
  27. 27.Best estimate of 542 + 123? (a) 400 (b) 600 (c) 800
  28. 28.Best estimate of 50 × 46? (a) 2500 (b) 250 (c) 25000
  29. 29.Best estimate of 21 × 27? (a) 6000 (b) 60 (c) 600
  30. 30.Best estimate of 51 × 40? (a) 20000 (b) 2000 (c) 200
  31. 31.Best estimate of 14 × 89? (a) 900 (b) 90 (c) 9000
  32. 32.Best estimate of 160 + 470? (a) 500 (b) 700 (c) 900
  33. 33.Best estimate of 154 + 694? (a) 900 (b) 1100 (c) 700
  34. 34.Best estimate of 27 × 94? (a) 2700 (b) 27000 (c) 270
  35. 35.Best estimate of 37 × 37? (a) 1600 (b) 16000 (c) 160
  36. 36.Best estimate of 51 × 12? (a) 5000 (b) 50 (c) 500
  37. 37.Best estimate of 564 + 147? (a) 700 (b) 900 (c) 500
  38. 38.Best estimate of 574 + 223? (a) 1000 (b) 800 (c) 600
  39. 39.Best estimate of 309 + 403? (a) 700 (b) 500 (c) 900
  40. 40.Best estimate of 601 + 677? (a) 1500 (b) 1300 (c) 1100

Answer key

  1. 1500
  2. 1400
  3. 2000
  4. 1800
  5. 600
  6. 6400
  7. 4500
  8. 1100
  9. 1200
  10. 600
  11. 500
  12. 1600
  13. 600
  14. 1400
  15. 200
  16. 1000
  17. 1000
  18. 900
  19. 7000
  20. 500
  21. 800
  22. 200
  23. 4800
  24. 600
  25. 800
  26. 1000
  27. 600
  28. 2500
  29. 600
  30. 2000
  31. 900
  32. 700
  33. 900
  34. 2700
  35. 1600
  36. 500
  37. 700
  38. 800
  39. 700
  40. 1300

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