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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 298 · 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 728 + 873? (a) 1600 (b) 1800 (c) 1400
  2. 2.Best estimate of 37 × 79? (a) 320 (b) 32000 (c) 3200
  3. 3.Best estimate of 375 + 629? (a) 1200 (b) 800 (c) 1000
  4. 4.Best estimate of 61 × 98? (a) 6000 (b) 600 (c) 60000
  5. 5.Best estimate of 873 + 269? (a) 1200 (b) 1400 (c) 1000
  6. 6.Best estimate of 816 + 327? (a) 1300 (b) 900 (c) 1100
  7. 7.Best estimate of 46 × 49? (a) 25000 (b) 2500 (c) 250
  8. 8.Best estimate of 91 × 81? (a) 72000 (b) 7200 (c) 720
  9. 9.Best estimate of 53 × 36? (a) 200 (b) 20000 (c) 2000
  10. 10.Best estimate of 318 + 834? (a) 1300 (b) 1100 (c) 900
  11. 11.Best estimate of 77 × 16? (a) 16000 (b) 160 (c) 1600
  12. 12.Best estimate of 319 + 183? (a) 300 (b) 500 (c) 700
  13. 13.Best estimate of 21 × 59? (a) 120 (b) 12000 (c) 1200
  14. 14.Best estimate of 838 + 309? (a) 1300 (b) 1100 (c) 900
  15. 15.Best estimate of 26 × 71? (a) 21000 (b) 2100 (c) 210
  16. 16.Best estimate of 322 + 615? (a) 700 (b) 1100 (c) 900
  17. 17.Best estimate of 444 + 327? (a) 500 (b) 900 (c) 700
  18. 18.Best estimate of 501 + 332? (a) 800 (b) 600 (c) 1000
  19. 19.Best estimate of 52 × 56? (a) 30000 (b) 300 (c) 3000
  20. 20.Best estimate of 612 + 534? (a) 1300 (b) 900 (c) 1100
  21. 21.Best estimate of 97 × 23? (a) 20000 (b) 200 (c) 2000
  22. 22.Best estimate of 611 + 446? (a) 1000 (b) 800 (c) 1200
  23. 23.Best estimate of 654 + 208? (a) 700 (b) 1100 (c) 900
  24. 24.Best estimate of 683 + 167? (a) 700 (b) 1100 (c) 900
  25. 25.Best estimate of 98 × 32? (a) 300 (b) 3000 (c) 30000
  26. 26.Best estimate of 857 + 262? (a) 1200 (b) 1000 (c) 1400
  27. 27.Best estimate of 335 + 255? (a) 800 (b) 600 (c) 400
  28. 28.Best estimate of 640 + 647? (a) 1400 (b) 1000 (c) 1200
  29. 29.Best estimate of 60 × 36? (a) 24000 (b) 240 (c) 2400
  30. 30.Best estimate of 13 × 33? (a) 30 (b) 3000 (c) 300
  31. 31.Best estimate of 91 × 57? (a) 540 (b) 5400 (c) 54000
  32. 32.Best estimate of 73 × 97? (a) 7000 (b) 70000 (c) 700
  33. 33.Best estimate of 88 × 42? (a) 360 (b) 3600 (c) 36000
  34. 34.Best estimate of 84 × 14? (a) 800 (b) 80 (c) 8000
  35. 35.Best estimate of 92 × 47? (a) 4500 (b) 450 (c) 45000
  36. 36.Best estimate of 36 × 61? (a) 24000 (b) 240 (c) 2400
  37. 37.Best estimate of 56 × 16? (a) 1200 (b) 12000 (c) 120
  38. 38.Best estimate of 504 + 383? (a) 700 (b) 1100 (c) 900
  39. 39.Best estimate of 34 × 77? (a) 240 (b) 24000 (c) 2400
  40. 40.Best estimate of 32 × 13? (a) 3000 (b) 300 (c) 30

Answer key

  1. 1600
  2. 3200
  3. 1000
  4. 6000
  5. 1200
  6. 1100
  7. 2500
  8. 7200
  9. 2000
  10. 1100
  11. 1600
  12. 500
  13. 1200
  14. 1100
  15. 2100
  16. 900
  17. 700
  18. 800
  19. 3000
  20. 1100
  21. 2000
  22. 1000
  23. 900
  24. 900
  25. 3000
  26. 1200
  27. 600
  28. 1200
  29. 2400
  30. 300
  31. 5400
  32. 7000
  33. 3600
  34. 800
  35. 4500
  36. 2400
  37. 1200
  38. 900
  39. 2400
  40. 300

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