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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 724 · 40 questions
TalentJR

How to do it in your head (Guess, divide, average): Division: round the divisor to the nearest ten and find the closest multiple of it. Square root: guess the nearest whole root, then divide the number by your guess. Average the guess and the answer of the division, and round to 1 decimal place.

NameDateTime takenScore ___ / 40
  1. 1.√98 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.9 (d) 9.8
  2. 2.√85 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.5
  3. 3.Best estimate of 1000 ÷ 24? (a) 5000 (b) 50 (c) 500
  4. 4.Best estimate of 2734 ÷ 36? (a) 6800 (b) 68 (c) 680
  5. 5.√61 to 1 decimal place? (a) 7.9 (b) 7.6 (c) 7.8 (d) 7.7
  6. 6.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.5 (d) 8.6
  7. 7.Best estimate of 2402 ÷ 28? (a) 80 (b) 800 (c) 8000
  8. 8.Best estimate of 1027 ÷ 64? (a) 1700 (b) 17 (c) 170
  9. 9.√96 to 1 decimal place? (a) 10.1 (b) 9.8 (c) 9.9 (d) 10.0
  10. 10.√62 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  11. 11.√43 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  12. 12.Best estimate of 944 ÷ 59? (a) 160 (b) 1600 (c) 16
  13. 13.Best estimate of 843 ÷ 28? (a) 28 (b) 2800 (c) 280
  14. 14.Best estimate of 1939 ÷ 56? (a) 320 (b) 32 (c) 3200
  15. 15.Best estimate of 2577 ÷ 46? (a) 5200 (b) 52 (c) 520
  16. 16.Best estimate of 569 ÷ 46? (a) 110 (b) 1100 (c) 11
  17. 17.Best estimate of 2502 ÷ 68? (a) 3600 (b) 360 (c) 36
  18. 18.√88 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.1
  19. 19.√70 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.2
  20. 20.Best estimate of 4252 ÷ 67? (a) 6100 (b) 61 (c) 610
  21. 21.Best estimate of 1606 ÷ 52? (a) 320 (b) 3200 (c) 32
  22. 22.√28 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.3 (d) 5.6
  23. 23.Best estimate of 1288 ÷ 82? (a) 1600 (b) 16 (c) 160
  24. 24.√45 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.7 (d) 6.5
  25. 25.Best estimate of 5043 ÷ 78? (a) 6300 (b) 63 (c) 630
  26. 26.Best estimate of 7190 ÷ 82? (a) 90 (b) 900 (c) 9000
  27. 27.√94 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.4
  28. 28.√74 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.5 (d) 8.7
  29. 29.Best estimate of 1922 ÷ 46? (a) 3800 (b) 38 (c) 380
  30. 30.Best estimate of 5518 ÷ 78? (a) 690 (b) 6900 (c) 69
  31. 31.√55 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.1 (d) 7.2
  32. 32.Best estimate of 1510 ÷ 51? (a) 300 (b) 3000 (c) 30
  33. 33.√67 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 8.2 (d) 7.9
  34. 34.Best estimate of 1681 ÷ 62? (a) 28 (b) 2800 (c) 280
  35. 35.Best estimate of 1428 ÷ 82? (a) 180 (b) 18 (c) 1800
  36. 36.√51 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 6.9 (d) 6.8
  37. 37.Best estimate of 1581 ÷ 71? (a) 230 (b) 2300 (c) 23
  38. 38.Best estimate of 1724 ÷ 89? (a) 190 (b) 19 (c) 1900
  39. 39.√27 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.0 (d) 5.3
  40. 40.Best estimate of 1383 ÷ 22? (a) 69 (b) 690 (c) 6900

Answer key

  1. 9.9
  2. 9.2
  3. 50
  4. 68
  5. 7.8
  6. 8.7
  7. 80
  8. 17
  9. 9.8
  10. 7.9
  11. 6.6
  12. 16
  13. 28
  14. 32
  15. 52
  16. 11
  17. 36
  18. 9.4
  19. 8.4
  20. 61
  21. 32
  22. 5.3
  23. 16
  24. 6.7
  25. 63
  26. 90
  27. 9.7
  28. 8.6
  29. 38
  30. 69
  31. 7.4
  32. 30
  33. 8.2
  34. 28
  35. 18
  36. 7.1
  37. 23
  38. 19
  39. 5.2
  40. 69

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