← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 336 · 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 748 + 225? (a) 900 (b) 700 (c) 1100
  2. 2.Best estimate of 18 × 56? (a) 1200 (b) 120 (c) 12000
  3. 3.Best estimate of 34 × 42? (a) 1200 (b) 120 (c) 12000
  4. 4.Best estimate of 769 + 439? (a) 1400 (b) 1000 (c) 1200
  5. 5.Best estimate of 18 × 67? (a) 1400 (b) 14000 (c) 140
  6. 6.Best estimate of 18 × 80? (a) 1600 (b) 16000 (c) 160
  7. 7.Best estimate of 50 × 13? (a) 500 (b) 5000 (c) 50
  8. 8.Best estimate of 52 × 46? (a) 2500 (b) 25000 (c) 250
  9. 9.Best estimate of 805 + 799? (a) 1800 (b) 1400 (c) 1600
  10. 10.Best estimate of 670 + 459? (a) 1400 (b) 1200 (c) 1000
  11. 11.Best estimate of 533 + 185? (a) 900 (b) 700 (c) 500
  12. 12.Best estimate of 257 + 159? (a) 500 (b) 300 (c) 700
  13. 13.Best estimate of 26 × 82? (a) 240 (b) 24000 (c) 2400
  14. 14.Best estimate of 493 + 775? (a) 1100 (b) 1500 (c) 1300
  15. 15.Best estimate of 520 + 880? (a) 1600 (b) 1200 (c) 1400
  16. 16.Best estimate of 79 × 22? (a) 1600 (b) 16000 (c) 160
  17. 17.Best estimate of 22 × 31? (a) 600 (b) 6000 (c) 60
  18. 18.Best estimate of 78 × 21? (a) 160 (b) 16000 (c) 1600
  19. 19.Best estimate of 16 × 83? (a) 1600 (b) 16000 (c) 160
  20. 20.Best estimate of 706 + 639? (a) 1300 (b) 1100 (c) 1500
  21. 21.Best estimate of 860 + 547? (a) 1400 (b) 1600 (c) 1200
  22. 22.Best estimate of 171 + 373? (a) 600 (b) 400 (c) 800
  23. 23.Best estimate of 442 + 791? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 259 + 602? (a) 1100 (b) 700 (c) 900
  25. 25.Best estimate of 51 × 18? (a) 1000 (b) 10000 (c) 100
  26. 26.Best estimate of 669 + 332? (a) 800 (b) 1200 (c) 1000
  27. 27.Best estimate of 31 × 67? (a) 2100 (b) 210 (c) 21000
  28. 28.Best estimate of 556 + 595? (a) 1000 (b) 1400 (c) 1200
  29. 29.Best estimate of 26 × 23? (a) 6000 (b) 60 (c) 600
  30. 30.Best estimate of 66 × 68? (a) 490 (b) 49000 (c) 4900
  31. 31.Best estimate of 278 + 745? (a) 1200 (b) 800 (c) 1000
  32. 32.Best estimate of 13 × 98? (a) 1000 (b) 100 (c) 10000
  33. 33.Best estimate of 83 × 29? (a) 24000 (b) 240 (c) 2400
  34. 34.Best estimate of 306 + 420? (a) 900 (b) 500 (c) 700
  35. 35.Best estimate of 24 × 94? (a) 1800 (b) 180 (c) 18000
  36. 36.Best estimate of 784 + 313? (a) 1100 (b) 900 (c) 1300
  37. 37.Best estimate of 517 + 135? (a) 800 (b) 600 (c) 400
  38. 38.Best estimate of 62 × 30? (a) 180 (b) 18000 (c) 1800
  39. 39.Best estimate of 334 + 176? (a) 700 (b) 300 (c) 500
  40. 40.Best estimate of 57 × 14? (a) 600 (b) 6000 (c) 60

Answer key

  1. 900
  2. 1200
  3. 1200
  4. 1200
  5. 1400
  6. 1600
  7. 500
  8. 2500
  9. 1600
  10. 1200
  11. 700
  12. 500
  13. 2400
  14. 1300
  15. 1400
  16. 1600
  17. 600
  18. 1600
  19. 1600
  20. 1300
  21. 1400
  22. 600
  23. 1200
  24. 900
  25. 1000
  26. 1000
  27. 2100
  28. 1200
  29. 600
  30. 4900
  31. 1000
  32. 1000
  33. 2400
  34. 700
  35. 1800
  36. 1100
  37. 600
  38. 1800
  39. 500
  40. 600

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