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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 442 · 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.√65 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.1 (d) 8.0
  2. 2.√35 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 5.8 (d) 5.9
  3. 3.√38 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.4 (d) 6.1
  4. 4.Best estimate of 1880 ÷ 36? (a) 47 (b) 470 (c) 4700
  5. 5.Best estimate of 762 ÷ 29? (a) 250 (b) 2500 (c) 25
  6. 6.Best estimate of 3894 ÷ 63? (a) 650 (b) 65 (c) 6500
  7. 7.Best estimate of 6201 ÷ 79? (a) 780 (b) 78 (c) 7800
  8. 8.√96 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 10.0 (d) 9.7
  9. 9.Best estimate of 777 ÷ 33? (a) 2600 (b) 260 (c) 26
  10. 10.√74 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.5 (d) 8.4
  11. 11.Best estimate of 3634 ÷ 51? (a) 730 (b) 73 (c) 7300
  12. 12.Best estimate of 2401 ÷ 26? (a) 8000 (b) 800 (c) 80
  13. 13.√75 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.8 (d) 8.6
  14. 14.√78 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 9.0
  15. 15.Best estimate of 5809 ÷ 76? (a) 730 (b) 73 (c) 7300
  16. 16.Best estimate of 7606 ÷ 86? (a) 8500 (b) 85 (c) 850
  17. 17.√61 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.6 (d) 7.8
  18. 18.Best estimate of 700 ÷ 27? (a) 2300 (b) 230 (c) 23
  19. 19.√48 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  20. 20.√34 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.8 (d) 5.5
  21. 21.√69 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.4 (d) 8.1
  22. 22.Best estimate of 1447 ÷ 52? (a) 290 (b) 29 (c) 2900
  23. 23.Best estimate of 4667 ÷ 77? (a) 580 (b) 5800 (c) 58
  24. 24.√27 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 4.9 (d) 5.0
  25. 25.√94 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.7 (d) 9.4
  26. 26.√71 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.1 (d) 8.3
  27. 27.Best estimate of 1163 ÷ 22? (a) 58 (b) 5800 (c) 580
  28. 28.Best estimate of 1206 ÷ 53? (a) 24 (b) 2400 (c) 240
  29. 29.Best estimate of 6739 ÷ 86? (a) 750 (b) 75 (c) 7500
  30. 30.√44 to 1 decimal place? (a) 6.4 (b) 6.7 (c) 6.5 (d) 6.6
  31. 31.Best estimate of 5615 ÷ 72? (a) 80 (b) 8000 (c) 800
  32. 32.√83 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 8.9
  33. 33.√24 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 5.1 (d) 4.8
  34. 34.Best estimate of 5822 ÷ 86? (a) 6500 (b) 650 (c) 65
  35. 35.√46 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 7.0 (d) 6.9
  36. 36.√86 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.5 (d) 9.3
  37. 37.Best estimate of 4963 ÷ 66? (a) 710 (b) 71 (c) 7100
  38. 38.Best estimate of 1019 ÷ 23? (a) 51 (b) 510 (c) 5100
  39. 39.√26 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.2 (d) 5.1
  40. 40.Best estimate of 777 ÷ 42? (a) 190 (b) 1900 (c) 19

Answer key

  1. 8.1
  2. 5.9
  3. 6.2
  4. 47
  5. 25
  6. 65
  7. 78
  8. 9.8
  9. 26
  10. 8.6
  11. 73
  12. 80
  13. 8.7
  14. 8.8
  15. 73
  16. 85
  17. 7.8
  18. 23
  19. 6.9
  20. 5.8
  21. 8.3
  22. 29
  23. 58
  24. 5.2
  25. 9.7
  26. 8.4
  27. 58
  28. 24
  29. 75
  30. 6.6
  31. 80
  32. 9.1
  33. 4.9
  34. 65
  35. 6.8
  36. 9.3
  37. 71
  38. 51
  39. 5.1
  40. 19

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