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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 651 · 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.Best estimate of 4503 ÷ 76? (a) 56 (b) 5600 (c) 560
  2. 2.Best estimate of 4675 ÷ 84? (a) 5800 (b) 580 (c) 58
  3. 3.√46 to 1 decimal place? (a) 6.5 (b) 6.8 (c) 6.7 (d) 6.6
  4. 4.Best estimate of 1551 ÷ 26? (a) 520 (b) 52 (c) 5200
  5. 5.√61 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 7.8 (d) 8.0
  6. 6.Best estimate of 1644 ÷ 79? (a) 210 (b) 2100 (c) 21
  7. 7.Best estimate of 3617 ÷ 84? (a) 4500 (b) 450 (c) 45
  8. 8.√38 to 1 decimal place? (a) 5.9 (b) 6.2 (c) 6.0 (d) 6.1
  9. 9.√90 to 1 decimal place? (a) 9.8 (b) 9.5 (c) 9.7 (d) 9.6
  10. 10.√22 to 1 decimal place? (a) 4.6 (b) 4.5 (c) 4.4 (d) 4.7
  11. 11.√58 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.8 (d) 7.6
  12. 12.√94 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.8 (d) 10.0
  13. 13.Best estimate of 7272 ÷ 82? (a) 9100 (b) 910 (c) 91
  14. 14.√78 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.1 (d) 8.8
  15. 15.Best estimate of 2074 ÷ 42? (a) 5200 (b) 52 (c) 520
  16. 16.Best estimate of 1735 ÷ 62? (a) 290 (b) 29 (c) 2900
  17. 17.√65 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.2 (d) 8.3
  18. 18.Best estimate of 449 ÷ 34? (a) 150 (b) 1500 (c) 15
  19. 19.√27 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.1 (d) 5.3
  20. 20.√51 to 1 decimal place? (a) 7.1 (b) 7.4 (c) 7.3 (d) 7.2
  21. 21.√24 to 1 decimal place? (a) 4.7 (b) 4.9 (c) 5.0 (d) 4.8
  22. 22.Best estimate of 565 ÷ 23? (a) 28 (b) 2800 (c) 280
  23. 23.Best estimate of 3812 ÷ 76? (a) 48 (b) 480 (c) 4800
  24. 24.Best estimate of 6902 ÷ 74? (a) 990 (b) 9900 (c) 99
  25. 25.Best estimate of 2284 ÷ 36? (a) 57 (b) 570 (c) 5700
  26. 26.Best estimate of 1534 ÷ 26? (a) 5100 (b) 51 (c) 510
  27. 27.Best estimate of 1223 ÷ 78? (a) 150 (b) 1500 (c) 15
  28. 28.Best estimate of 7283 ÷ 78? (a) 9100 (b) 910 (c) 91
  29. 29.√29 to 1 decimal place? (a) 5.1 (b) 5.4 (c) 5.2 (d) 5.3
  30. 30.√48 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.6 (d) 6.8
  31. 31.Best estimate of 2439 ÷ 56? (a) 4100 (b) 41 (c) 410
  32. 32.Best estimate of 2154 ÷ 59? (a) 3600 (b) 36 (c) 360
  33. 33.Best estimate of 6839 ÷ 72? (a) 9800 (b) 98 (c) 980
  34. 34.Best estimate of 4301 ÷ 76? (a) 5400 (b) 540 (c) 54
  35. 35.Best estimate of 4834 ÷ 56? (a) 81 (b) 810 (c) 8100
  36. 36.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  37. 37.√70 to 1 decimal place? (a) 8.1 (b) 8.3 (c) 8.4 (d) 8.2
  38. 38.Best estimate of 4561 ÷ 52? (a) 9100 (b) 91 (c) 910
  39. 39.Best estimate of 5196 ÷ 62? (a) 8700 (b) 870 (c) 87
  40. 40.Best estimate of 1383 ÷ 37? (a) 350 (b) 3500 (c) 35

Answer key

  1. 56
  2. 58
  3. 6.8
  4. 52
  5. 7.8
  6. 21
  7. 45
  8. 6.2
  9. 9.5
  10. 4.7
  11. 7.6
  12. 9.7
  13. 91
  14. 8.8
  15. 52
  16. 29
  17. 8.1
  18. 15
  19. 5.2
  20. 7.1
  21. 4.9
  22. 28
  23. 48
  24. 99
  25. 57
  26. 51
  27. 15
  28. 91
  29. 5.4
  30. 6.9
  31. 41
  32. 36
  33. 98
  34. 54
  35. 81
  36. 8.7
  37. 8.4
  38. 91
  39. 87
  40. 35

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