← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 111 · 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 642 + 658? (a) 1500 (b) 1100 (c) 1300
  2. 2.Best estimate of 338 + 532? (a) 600 (b) 1000 (c) 800
  3. 3.Best estimate of 94 × 14? (a) 900 (b) 9000 (c) 90
  4. 4.Best estimate of 447 + 388? (a) 800 (b) 600 (c) 1000
  5. 5.Best estimate of 86 × 28? (a) 270 (b) 2700 (c) 27000
  6. 6.Best estimate of 830 + 573? (a) 1200 (b) 1400 (c) 1600
  7. 7.Best estimate of 379 + 429? (a) 600 (b) 800 (c) 1000
  8. 8.Best estimate of 17 × 20? (a) 4000 (b) 40 (c) 400
  9. 9.Best estimate of 29 × 29? (a) 900 (b) 90 (c) 9000
  10. 10.Best estimate of 37 × 27? (a) 120 (b) 12000 (c) 1200
  11. 11.Best estimate of 26 × 90? (a) 2700 (b) 27000 (c) 270
  12. 12.Best estimate of 181 + 763? (a) 800 (b) 1000 (c) 1200
  13. 13.Best estimate of 84 × 36? (a) 32000 (b) 3200 (c) 320
  14. 14.Best estimate of 78 × 33? (a) 240 (b) 24000 (c) 2400
  15. 15.Best estimate of 829 + 769? (a) 1600 (b) 1800 (c) 1400
  16. 16.Best estimate of 155 + 151? (a) 400 (b) 600 (c) 200
  17. 17.Best estimate of 552 + 146? (a) 900 (b) 700 (c) 500
  18. 18.Best estimate of 56 × 57? (a) 3600 (b) 36000 (c) 360
  19. 19.Best estimate of 628 + 128? (a) 700 (b) 900 (c) 500
  20. 20.Best estimate of 16 × 36? (a) 800 (b) 80 (c) 8000
  21. 21.Best estimate of 593 + 457? (a) 1100 (b) 1300 (c) 900
  22. 22.Best estimate of 88 × 14? (a) 900 (b) 9000 (c) 90
  23. 23.Best estimate of 625 + 828? (a) 1600 (b) 1400 (c) 1200
  24. 24.Best estimate of 21 × 50? (a) 100 (b) 1000 (c) 10000
  25. 25.Best estimate of 502 + 218? (a) 900 (b) 500 (c) 700
  26. 26.Best estimate of 54 × 61? (a) 300 (b) 3000 (c) 30000
  27. 27.Best estimate of 795 + 572? (a) 1600 (b) 1200 (c) 1400
  28. 28.Best estimate of 51 × 76? (a) 40000 (b) 400 (c) 4000
  29. 29.Best estimate of 87 × 33? (a) 27000 (b) 270 (c) 2700
  30. 30.Best estimate of 549 + 401? (a) 900 (b) 700 (c) 1100
  31. 31.Best estimate of 90 × 50? (a) 45000 (b) 450 (c) 4500
  32. 32.Best estimate of 826 + 528? (a) 1300 (b) 1100 (c) 1500
  33. 33.Best estimate of 12 × 32? (a) 3000 (b) 300 (c) 30
  34. 34.Best estimate of 54 × 32? (a) 1500 (b) 15000 (c) 150
  35. 35.Best estimate of 453 + 502? (a) 1200 (b) 800 (c) 1000
  36. 36.Best estimate of 56 × 48? (a) 3000 (b) 300 (c) 30000
  37. 37.Best estimate of 16 × 74? (a) 1400 (b) 14000 (c) 140
  38. 38.Best estimate of 33 × 64? (a) 18000 (b) 1800 (c) 180
  39. 39.Best estimate of 229 + 408? (a) 600 (b) 800 (c) 400
  40. 40.Best estimate of 42 × 42? (a) 1600 (b) 16000 (c) 160

Answer key

  1. 1300
  2. 800
  3. 900
  4. 800
  5. 2700
  6. 1400
  7. 800
  8. 400
  9. 900
  10. 1200
  11. 2700
  12. 1000
  13. 3200
  14. 2400
  15. 1600
  16. 400
  17. 700
  18. 3600
  19. 700
  20. 800
  21. 1100
  22. 900
  23. 1400
  24. 1000
  25. 700
  26. 3000
  27. 1400
  28. 4000
  29. 2700
  30. 900
  31. 4500
  32. 1300
  33. 300
  34. 1500
  35. 1000
  36. 3000
  37. 1400
  38. 1800
  39. 600
  40. 1600

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