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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 802 · 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 6435 ÷ 72? (a) 920 (b) 9200 (c) 92
  2. 2.√90 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.4 (d) 9.3
  3. 3.√83 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.3 (d) 9.2
  4. 4.√53 to 1 decimal place? (a) 7.3 (b) 7.2 (c) 7.0 (d) 7.1
  5. 5.Best estimate of 1625 ÷ 72? (a) 2300 (b) 230 (c) 23
  6. 6.Best estimate of 2364 ÷ 72? (a) 34 (b) 3400 (c) 340
  7. 7.Best estimate of 577 ÷ 42? (a) 14 (b) 140 (c) 1400
  8. 8.Best estimate of 2731 ÷ 41? (a) 68 (b) 6800 (c) 680
  9. 9.√26 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.2 (d) 5.0
  10. 10.Best estimate of 2982 ÷ 87? (a) 330 (b) 3300 (c) 33
  11. 11.√70 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  12. 12.Best estimate of 1084 ÷ 23? (a) 5400 (b) 54 (c) 540
  13. 13.√24 to 1 decimal place? (a) 5.1 (b) 4.8 (c) 4.9 (d) 5.0
  14. 14.Best estimate of 1353 ÷ 43? (a) 3400 (b) 34 (c) 340
  15. 15.Best estimate of 1049 ÷ 76? (a) 130 (b) 1300 (c) 13
  16. 16.√67 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 7.9 (d) 8.2
  17. 17.Best estimate of 3427 ÷ 52? (a) 6900 (b) 690 (c) 69
  18. 18.Best estimate of 5312 ÷ 88? (a) 590 (b) 59 (c) 5900
  19. 19.√61 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 7.7 (d) 7.8
  20. 20.Best estimate of 5982 ÷ 76? (a) 75 (b) 7500 (c) 750
  21. 21.Best estimate of 1339 ÷ 79? (a) 17 (b) 170 (c) 1700
  22. 22.Best estimate of 2480 ÷ 32? (a) 8300 (b) 830 (c) 83
  23. 23.Best estimate of 1445 ÷ 57? (a) 24 (b) 240 (c) 2400
  24. 24.Best estimate of 2797 ÷ 49? (a) 560 (b) 56 (c) 5600
  25. 25.Best estimate of 6362 ÷ 72? (a) 910 (b) 91 (c) 9100
  26. 26.Best estimate of 3357 ÷ 64? (a) 560 (b) 5600 (c) 56
  27. 27.√76 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.6 (d) 8.8
  28. 28.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 9.6
  29. 29.Best estimate of 2204 ÷ 26? (a) 73 (b) 730 (c) 7300
  30. 30.Best estimate of 3672 ÷ 79? (a) 4600 (b) 46 (c) 460
  31. 31.√40 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.6 (d) 6.4
  32. 32.Best estimate of 1110 ÷ 56? (a) 190 (b) 19 (c) 1900
  33. 33.√31 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.7 (d) 5.6
  34. 34.Best estimate of 880 ÷ 42? (a) 220 (b) 22 (c) 2200
  35. 35.√32 to 1 decimal place? (a) 5.8 (b) 5.5 (c) 5.7 (d) 5.6
  36. 36.Best estimate of 1515 ÷ 34? (a) 51 (b) 510 (c) 5100
  37. 37.√87 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.1 (d) 9.2
  38. 38.√52 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 6.9 (d) 7.0
  39. 39.√22 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 4.7 (d) 5.0
  40. 40.Best estimate of 3572 ÷ 81? (a) 450 (b) 4500 (c) 45

Answer key

  1. 92
  2. 9.5
  3. 9.1
  4. 7.3
  5. 23
  6. 34
  7. 14
  8. 68
  9. 5.1
  10. 33
  11. 8.4
  12. 54
  13. 4.9
  14. 34
  15. 13
  16. 8.2
  17. 69
  18. 59
  19. 7.8
  20. 75
  21. 17
  22. 83
  23. 24
  24. 56
  25. 91
  26. 56
  27. 8.7
  28. 9.9
  29. 73
  30. 46
  31. 6.3
  32. 19
  33. 5.6
  34. 22
  35. 5.7
  36. 51
  37. 9.3
  38. 7.2
  39. 4.7
  40. 45

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