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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 760 · 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 1093 ÷ 21? (a) 5500 (b) 550 (c) 55
  2. 2.√58 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.3
  3. 3.√69 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  4. 4.√42 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.5 (d) 6.7
  5. 5.Best estimate of 1523 ÷ 58? (a) 250 (b) 2500 (c) 25
  6. 6.√79 to 1 decimal place? (a) 8.8 (b) 9.0 (c) 8.7 (d) 8.9
  7. 7.√45 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.8 (d) 6.7
  8. 8.Best estimate of 776 ÷ 61? (a) 13 (b) 130 (c) 1300
  9. 9.√29 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.4
  10. 10.Best estimate of 761 ÷ 23? (a) 380 (b) 38 (c) 3800
  11. 11.√92 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.8 (d) 9.5
  12. 12.√70 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.4 (d) 8.1
  13. 13.√76 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.8 (d) 8.5
  14. 14.Best estimate of 580 ÷ 24? (a) 2900 (b) 29 (c) 290
  15. 15.√31 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 5.6 (d) 5.8
  16. 16.Best estimate of 1966 ÷ 47? (a) 39 (b) 390 (c) 3900
  17. 17.Best estimate of 2122 ÷ 47? (a) 42 (b) 420 (c) 4200
  18. 18.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.4 (d) 9.2
  19. 19.√48 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.8 (d) 7.1
  20. 20.Best estimate of 1695 ÷ 74? (a) 2400 (b) 240 (c) 24
  21. 21.Best estimate of 3784 ÷ 53? (a) 76 (b) 7600 (c) 760
  22. 22.Best estimate of 1555 ÷ 48? (a) 31 (b) 310 (c) 3100
  23. 23.Best estimate of 1768 ÷ 46? (a) 3500 (b) 35 (c) 350
  24. 24.Best estimate of 671 ÷ 38? (a) 170 (b) 17 (c) 1700
  25. 25.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.9 (d) 9.6
  26. 26.√88 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.4
  27. 27.Best estimate of 860 ÷ 26? (a) 290 (b) 2900 (c) 29
  28. 28.Best estimate of 1695 ÷ 73? (a) 240 (b) 2400 (c) 24
  29. 29.Best estimate of 3145 ÷ 54? (a) 630 (b) 63 (c) 6300
  30. 30.Best estimate of 2174 ÷ 62? (a) 3600 (b) 360 (c) 36
  31. 31.Best estimate of 1529 ÷ 84? (a) 19 (b) 190 (c) 1900
  32. 32.Best estimate of 4543 ÷ 56? (a) 76 (b) 7600 (c) 760
  33. 33.√52 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.4 (d) 7.1
  34. 34.√26 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.4 (d) 5.2
  35. 35.Best estimate of 2244 ÷ 66? (a) 3200 (b) 32 (c) 320
  36. 36.√66 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 8.1 (d) 8.0
  37. 37.Best estimate of 810 ÷ 27? (a) 2700 (b) 27 (c) 270
  38. 38.Best estimate of 1718 ÷ 42? (a) 4300 (b) 430 (c) 43
  39. 39.√72 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.6 (d) 8.3
  40. 40.Best estimate of 4552 ÷ 48? (a) 91 (b) 910 (c) 9100

Answer key

  1. 55
  2. 7.6
  3. 8.3
  4. 6.5
  5. 25
  6. 8.9
  7. 6.7
  8. 13
  9. 5.4
  10. 38
  11. 9.6
  12. 8.4
  13. 8.7
  14. 29
  15. 5.6
  16. 39
  17. 42
  18. 9.1
  19. 6.9
  20. 24
  21. 76
  22. 31
  23. 35
  24. 17
  25. 9.7
  26. 9.4
  27. 29
  28. 24
  29. 63
  30. 36
  31. 19
  32. 76
  33. 7.2
  34. 5.1
  35. 32
  36. 8.1
  37. 27
  38. 43
  39. 8.5
  40. 91

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