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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 399 · 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 1470 ÷ 56? (a) 2500 (b) 25 (c) 250
  2. 2.Best estimate of 3056 ÷ 52? (a) 610 (b) 61 (c) 6100
  3. 3.Best estimate of 969 ÷ 57? (a) 160 (b) 16 (c) 1600
  4. 4.√65 to 1 decimal place? (a) 8.2 (b) 7.9 (c) 8.0 (d) 8.1
  5. 5.√89 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.3 (d) 9.4
  6. 6.Best estimate of 2287 ÷ 73? (a) 330 (b) 3300 (c) 33
  7. 7.Best estimate of 2054 ÷ 36? (a) 51 (b) 510 (c) 5100
  8. 8.Best estimate of 1856 ÷ 27? (a) 62 (b) 6200 (c) 620
  9. 9.Best estimate of 2118 ÷ 32? (a) 7100 (b) 710 (c) 71
  10. 10.√72 to 1 decimal place? (a) 8.5 (b) 8.8 (c) 8.7 (d) 8.6
  11. 11.Best estimate of 5258 ÷ 56? (a) 88 (b) 8800 (c) 880
  12. 12.Best estimate of 6086 ÷ 72? (a) 8700 (b) 87 (c) 870
  13. 13.Best estimate of 709 ÷ 26? (a) 2400 (b) 24 (c) 240
  14. 14.√48 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 6.9
  15. 15.Best estimate of 6309 ÷ 69? (a) 9000 (b) 900 (c) 90
  16. 16.√84 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.4 (d) 9.3
  17. 17.Best estimate of 3379 ÷ 38? (a) 84 (b) 840 (c) 8400
  18. 18.Best estimate of 6859 ÷ 76? (a) 860 (b) 86 (c) 8600
  19. 19.Best estimate of 6823 ÷ 89? (a) 760 (b) 7600 (c) 76
  20. 20.√50 to 1 decimal place? (a) 7.4 (b) 7.1 (c) 7.3 (d) 7.2
  21. 21.Best estimate of 2091 ÷ 36? (a) 52 (b) 520 (c) 5200
  22. 22.√92 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.4
  23. 23.Best estimate of 1037 ÷ 66? (a) 15 (b) 1500 (c) 150
  24. 24.√34 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.8 (d) 5.9
  25. 25.Best estimate of 1794 ÷ 23? (a) 9000 (b) 900 (c) 90
  26. 26.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.0 (d) 7.7
  27. 27.√26 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.0 (d) 5.1
  28. 28.√94 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 9.7
  29. 29.Best estimate of 2453 ÷ 36? (a) 61 (b) 610 (c) 6100
  30. 30.Best estimate of 2254 ÷ 86? (a) 2500 (b) 25 (c) 250
  31. 31.√38 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.0 (d) 6.3
  32. 32.√58 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.5 (d) 7.3
  33. 33.Best estimate of 2620 ÷ 33? (a) 8700 (b) 87 (c) 870
  34. 34.√21 to 1 decimal place? (a) 4.9 (b) 4.6 (c) 4.8 (d) 4.7
  35. 35.Best estimate of 1007 ÷ 33? (a) 340 (b) 3400 (c) 34
  36. 36.Best estimate of 4394 ÷ 47? (a) 880 (b) 88 (c) 8800
  37. 37.Best estimate of 1573 ÷ 54? (a) 31 (b) 310 (c) 3100
  38. 38.Best estimate of 1287 ÷ 24? (a) 6400 (b) 64 (c) 640
  39. 39.Best estimate of 2476 ÷ 37? (a) 6200 (b) 62 (c) 620
  40. 40.√23 to 1 decimal place? (a) 5.0 (b) 4.8 (c) 5.1 (d) 4.9

Answer key

  1. 25
  2. 61
  3. 16
  4. 8.1
  5. 9.4
  6. 33
  7. 51
  8. 62
  9. 71
  10. 8.5
  11. 88
  12. 87
  13. 24
  14. 6.9
  15. 90
  16. 9.2
  17. 84
  18. 86
  19. 76
  20. 7.1
  21. 52
  22. 9.6
  23. 15
  24. 5.8
  25. 90
  26. 7.8
  27. 5.1
  28. 9.7
  29. 61
  30. 25
  31. 6.2
  32. 7.6
  33. 87
  34. 4.6
  35. 34
  36. 88
  37. 31
  38. 64
  39. 62
  40. 4.8

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