← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 58 · 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 82 × 33? (a) 24000 (b) 240 (c) 2400
  2. 2.Best estimate of 39 × 93? (a) 3600 (b) 36000 (c) 360
  3. 3.Best estimate of 298 + 389? (a) 900 (b) 500 (c) 700
  4. 4.Best estimate of 145 + 283? (a) 600 (b) 400 (c) 200
  5. 5.Best estimate of 13 × 78? (a) 800 (b) 80 (c) 8000
  6. 6.Best estimate of 70 × 18? (a) 1400 (b) 14000 (c) 140
  7. 7.Best estimate of 16 × 67? (a) 14000 (b) 140 (c) 1400
  8. 8.Best estimate of 61 × 81? (a) 4800 (b) 48000 (c) 480
  9. 9.Best estimate of 17 × 71? (a) 1400 (b) 14000 (c) 140
  10. 10.Best estimate of 639 + 820? (a) 1200 (b) 1400 (c) 1600
  11. 11.Best estimate of 330 + 585? (a) 1100 (b) 700 (c) 900
  12. 12.Best estimate of 557 + 657? (a) 1500 (b) 1300 (c) 1100
  13. 13.Best estimate of 170 + 244? (a) 200 (b) 600 (c) 400
  14. 14.Best estimate of 606 + 556? (a) 1200 (b) 1400 (c) 1000
  15. 15.Best estimate of 520 + 200? (a) 900 (b) 700 (c) 500
  16. 16.Best estimate of 43 × 58? (a) 24000 (b) 240 (c) 2400
  17. 17.Best estimate of 563 + 287? (a) 1100 (b) 900 (c) 700
  18. 18.Best estimate of 127 + 870? (a) 800 (b) 1000 (c) 1200
  19. 19.Best estimate of 412 + 834? (a) 1400 (b) 1000 (c) 1200
  20. 20.Best estimate of 230 + 712? (a) 700 (b) 1100 (c) 900
  21. 21.Best estimate of 763 + 515? (a) 1300 (b) 1100 (c) 1500
  22. 22.Best estimate of 76 × 71? (a) 56000 (b) 5600 (c) 560
  23. 23.Best estimate of 43 × 14? (a) 40 (b) 400 (c) 4000
  24. 24.Best estimate of 58 × 58? (a) 3600 (b) 36000 (c) 360
  25. 25.Best estimate of 60 × 14? (a) 60 (b) 6000 (c) 600
  26. 26.Best estimate of 29 × 18? (a) 6000 (b) 600 (c) 60
  27. 27.Best estimate of 70 × 86? (a) 63000 (b) 6300 (c) 630
  28. 28.Best estimate of 92 × 87? (a) 8100 (b) 810 (c) 81000
  29. 29.Best estimate of 331 + 641? (a) 900 (b) 1100 (c) 700
  30. 30.Best estimate of 324 + 157? (a) 300 (b) 700 (c) 500
  31. 31.Best estimate of 797 + 757? (a) 1400 (b) 1800 (c) 1600
  32. 32.Best estimate of 188 + 186? (a) 400 (b) 600 (c) 200
  33. 33.Best estimate of 620 + 452? (a) 1300 (b) 900 (c) 1100
  34. 34.Best estimate of 877 + 585? (a) 1300 (b) 1700 (c) 1500
  35. 35.Best estimate of 91 × 37? (a) 360 (b) 3600 (c) 36000
  36. 36.Best estimate of 31 × 68? (a) 2100 (b) 210 (c) 21000
  37. 37.Best estimate of 16 × 29? (a) 6000 (b) 600 (c) 60
  38. 38.Best estimate of 66 × 24? (a) 140 (b) 1400 (c) 14000
  39. 39.Best estimate of 518 + 766? (a) 1500 (b) 1100 (c) 1300
  40. 40.Best estimate of 331 + 683? (a) 1000 (b) 1200 (c) 800

Answer key

  1. 2400
  2. 3600
  3. 700
  4. 400
  5. 800
  6. 1400
  7. 1400
  8. 4800
  9. 1400
  10. 1400
  11. 900
  12. 1300
  13. 400
  14. 1200
  15. 700
  16. 2400
  17. 900
  18. 1000
  19. 1200
  20. 900
  21. 1300
  22. 5600
  23. 400
  24. 3600
  25. 600
  26. 600
  27. 6300
  28. 8100
  29. 900
  30. 500
  31. 1600
  32. 400
  33. 1100
  34. 1500
  35. 3600
  36. 2100
  37. 600
  38. 1400
  39. 1300
  40. 1000

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