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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 281 · 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 5101 ÷ 58? (a) 8500 (b) 850 (c) 85
  2. 2.Best estimate of 1331 ÷ 82? (a) 170 (b) 17 (c) 1700
  3. 3.√34 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.7 (d) 5.8
  4. 4.Best estimate of 1402 ÷ 33? (a) 470 (b) 4700 (c) 47
  5. 5.Best estimate of 5110 ÷ 67? (a) 7300 (b) 73 (c) 730
  6. 6.√86 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.1
  7. 7.√65 to 1 decimal place? (a) 8.0 (b) 7.8 (c) 8.1 (d) 7.9
  8. 8.√50 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 6.8 (d) 6.9
  9. 9.Best estimate of 2452 ÷ 34? (a) 820 (b) 82 (c) 8200
  10. 10.Best estimate of 4521 ÷ 48? (a) 90 (b) 9000 (c) 900
  11. 11.Best estimate of 2071 ÷ 56? (a) 350 (b) 35 (c) 3500
  12. 12.Best estimate of 2905 ÷ 51? (a) 5800 (b) 58 (c) 580
  13. 13.√24 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 5.1
  14. 14.√55 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.5 (d) 7.4
  15. 15.Best estimate of 2240 ÷ 61? (a) 37 (b) 3700 (c) 370
  16. 16.√29 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.5 (d) 5.2
  17. 17.Best estimate of 760 ÷ 26? (a) 25 (b) 2500 (c) 250
  18. 18.√87 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.1
  19. 19.√98 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.8 (d) 10.0
  20. 20.√94 to 1 decimal place? (a) 9.7 (b) 9.4 (c) 9.5 (d) 9.6
  21. 21.√26 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 5.2 (d) 4.9
  22. 22.Best estimate of 3447 ÷ 72? (a) 4900 (b) 490 (c) 49
  23. 23.Best estimate of 2741 ÷ 31? (a) 9100 (b) 91 (c) 910
  24. 24.Best estimate of 3407 ÷ 36? (a) 85 (b) 850 (c) 8500
  25. 25.√66 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.2 (d) 8.3
  26. 26.Best estimate of 618 ÷ 39? (a) 1500 (b) 150 (c) 15
  27. 27.Best estimate of 1322 ÷ 52? (a) 260 (b) 26 (c) 2600
  28. 28.√58 to 1 decimal place? (a) 7.7 (b) 7.5 (c) 7.6 (d) 7.4
  29. 29.Best estimate of 2789 ÷ 36? (a) 7000 (b) 700 (c) 70
  30. 30.Best estimate of 3103 ÷ 68? (a) 440 (b) 4400 (c) 44
  31. 31.Best estimate of 1308 ÷ 23? (a) 6500 (b) 650 (c) 65
  32. 32.√71 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.4 (d) 8.5
  33. 33.Best estimate of 3587 ÷ 82? (a) 4500 (b) 45 (c) 450
  34. 34.Best estimate of 7927 ÷ 88? (a) 88 (b) 8800 (c) 880
  35. 35.Best estimate of 680 ÷ 32? (a) 2300 (b) 230 (c) 23
  36. 36.√51 to 1 decimal place? (a) 6.8 (b) 7.1 (c) 7.0 (d) 6.9
  37. 37.√22 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 5.0 (d) 4.9
  38. 38.√40 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.4 (d) 6.1
  39. 39.Best estimate of 1275 ÷ 63? (a) 210 (b) 2100 (c) 21
  40. 40.Best estimate of 1528 ÷ 24? (a) 76 (b) 760 (c) 7600

Answer key

  1. 85
  2. 17
  3. 5.8
  4. 47
  5. 73
  6. 9.3
  7. 8.1
  8. 7.1
  9. 82
  10. 90
  11. 35
  12. 58
  13. 4.9
  14. 7.4
  15. 37
  16. 5.4
  17. 25
  18. 9.3
  19. 9.9
  20. 9.7
  21. 5.1
  22. 49
  23. 91
  24. 85
  25. 8.1
  26. 15
  27. 26
  28. 7.6
  29. 70
  30. 44
  31. 65
  32. 8.4
  33. 45
  34. 88
  35. 23
  36. 7.1
  37. 4.7
  38. 6.3
  39. 21
  40. 76

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