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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 573 · 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 2934 ÷ 42? (a) 73 (b) 730 (c) 7300
  2. 2.Best estimate of 1430 ÷ 53? (a) 2900 (b) 290 (c) 29
  3. 3.Best estimate of 1176 ÷ 24? (a) 59 (b) 590 (c) 5900
  4. 4.√63 to 1 decimal place? (a) 7.6 (b) 7.9 (c) 7.7 (d) 7.8
  5. 5.√31 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.4 (d) 5.7
  6. 6.Best estimate of 3133 ÷ 59? (a) 520 (b) 5200 (c) 52
  7. 7.√50 to 1 decimal place? (a) 7.1 (b) 7.0 (c) 6.9 (d) 6.8
  8. 8.Best estimate of 3698 ÷ 64? (a) 62 (b) 620 (c) 6200
  9. 9.Best estimate of 798 ÷ 34? (a) 270 (b) 27 (c) 2700
  10. 10.Best estimate of 2549 ÷ 62? (a) 420 (b) 42 (c) 4200
  11. 11.Best estimate of 722 ÷ 33? (a) 24 (b) 240 (c) 2400
  12. 12.√70 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.4 (d) 8.1
  13. 13.Best estimate of 636 ÷ 48? (a) 1300 (b) 13 (c) 130
  14. 14.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  15. 15.Best estimate of 3902 ÷ 76? (a) 490 (b) 4900 (c) 49
  16. 16.Best estimate of 1684 ÷ 69? (a) 240 (b) 2400 (c) 24
  17. 17.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.5 (d) 8.6
  18. 18.Best estimate of 1512 ÷ 29? (a) 5000 (b) 50 (c) 500
  19. 19.√56 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.7 (d) 7.6
  20. 20.√52 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 7.1 (d) 7.2
  21. 21.√27 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.5 (d) 5.3
  22. 22.√45 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.5
  23. 23.√20 to 1 decimal place? (a) 4.5 (b) 4.7 (c) 4.8 (d) 4.6
  24. 24.Best estimate of 452 ÷ 24? (a) 230 (b) 23 (c) 2300
  25. 25.√96 to 1 decimal place? (a) 10.0 (b) 10.1 (c) 9.9 (d) 9.8
  26. 26.√35 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 5.8 (d) 5.6
  27. 27.Best estimate of 4471 ÷ 78? (a) 5600 (b) 56 (c) 560
  28. 28.√48 to 1 decimal place? (a) 7.0 (b) 6.8 (c) 7.1 (d) 6.9
  29. 29.√55 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.6
  30. 30.√43 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.4
  31. 31.Best estimate of 890 ÷ 43? (a) 2200 (b) 22 (c) 220
  32. 32.√77 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.8 (d) 8.9
  33. 33.√42 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.8 (d) 6.7
  34. 34.√79 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.6 (d) 8.8
  35. 35.Best estimate of 1248 ÷ 24? (a) 6200 (b) 62 (c) 620
  36. 36.Best estimate of 2897 ÷ 38? (a) 72 (b) 7200 (c) 720
  37. 37.√67 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.1 (d) 8.2
  38. 38.Best estimate of 2709 ÷ 37? (a) 68 (b) 680 (c) 6800
  39. 39.Best estimate of 2444 ÷ 28? (a) 810 (b) 81 (c) 8100
  40. 40.Best estimate of 1357 ÷ 48? (a) 27 (b) 270 (c) 2700

Answer key

  1. 73
  2. 29
  3. 59
  4. 7.9
  5. 5.6
  6. 52
  7. 7.1
  8. 62
  9. 27
  10. 42
  11. 24
  12. 8.4
  13. 13
  14. 7.8
  15. 49
  16. 24
  17. 8.7
  18. 50
  19. 7.5
  20. 7.2
  21. 5.2
  22. 6.7
  23. 4.5
  24. 23
  25. 9.8
  26. 5.9
  27. 56
  28. 6.9
  29. 7.4
  30. 6.6
  31. 22
  32. 8.8
  33. 6.5
  34. 8.9
  35. 62
  36. 72
  37. 8.2
  38. 68
  39. 81
  40. 27

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