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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 407 · 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 1341 ÷ 64? (a) 2200 (b) 220 (c) 22
  2. 2.Best estimate of 6471 ÷ 72? (a) 920 (b) 9200 (c) 92
  3. 3.Best estimate of 1601 ÷ 41? (a) 40 (b) 4000 (c) 400
  4. 4.Best estimate of 2511 ÷ 34? (a) 8400 (b) 84 (c) 840
  5. 5.√26 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.2 (d) 5.0
  6. 6.Best estimate of 1883 ÷ 73? (a) 270 (b) 27 (c) 2700
  7. 7.Best estimate of 1122 ÷ 31? (a) 37 (b) 3700 (c) 370
  8. 8.√55 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.4
  9. 9.Best estimate of 996 ÷ 26? (a) 33 (b) 330 (c) 3300
  10. 10.Best estimate of 1295 ÷ 42? (a) 3200 (b) 32 (c) 320
  11. 11.√29 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.4
  12. 12.√84 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.4
  13. 13.Best estimate of 4547 ÷ 86? (a) 5100 (b) 51 (c) 510
  14. 14.Best estimate of 1310 ÷ 27? (a) 440 (b) 44 (c) 4400
  15. 15.√53 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.4 (d) 7.5
  16. 16.√35 to 1 decimal place? (a) 5.7 (b) 6.0 (c) 5.9 (d) 5.8
  17. 17.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.0
  18. 18.Best estimate of 1793 ÷ 56? (a) 300 (b) 3000 (c) 30
  19. 19.Best estimate of 965 ÷ 29? (a) 320 (b) 3200 (c) 32
  20. 20.Best estimate of 2083 ÷ 82? (a) 260 (b) 26 (c) 2600
  21. 21.√22 to 1 decimal place? (a) 4.9 (b) 4.7 (c) 4.8 (d) 5.0
  22. 22.Best estimate of 5006 ÷ 77? (a) 63 (b) 6300 (c) 630
  23. 23.Best estimate of 2335 ÷ 79? (a) 290 (b) 2900 (c) 29
  24. 24.√59 to 1 decimal place? (a) 8.0 (b) 7.7 (c) 7.8 (d) 7.9
  25. 25.√30 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.4 (d) 5.2
  26. 26.√78 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 8.8 (d) 9.0
  27. 27.√50 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 6.8 (d) 7.0
  28. 28.√58 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.5 (d) 7.3
  29. 29.Best estimate of 2582 ÷ 71? (a) 370 (b) 3700 (c) 37
  30. 30.Best estimate of 3852 ÷ 73? (a) 55 (b) 550 (c) 5500
  31. 31.Best estimate of 793 ÷ 32? (a) 2600 (b) 26 (c) 260
  32. 32.Best estimate of 4784 ÷ 87? (a) 53 (b) 530 (c) 5300
  33. 33.Best estimate of 2295 ÷ 52? (a) 4600 (b) 460 (c) 46
  34. 34.Best estimate of 1868 ÷ 78? (a) 230 (b) 2300 (c) 23
  35. 35.√62 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  36. 36.√24 to 1 decimal place? (a) 4.7 (b) 4.9 (c) 4.8 (d) 5.0
  37. 37.Best estimate of 1439 ÷ 47? (a) 290 (b) 2900 (c) 29
  38. 38.√42 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.2 (d) 6.4
  39. 39.√92 to 1 decimal place? (a) 9.7 (b) 9.5 (c) 9.6 (d) 9.4
  40. 40.Best estimate of 354 ÷ 23? (a) 1800 (b) 18 (c) 180

Answer key

  1. 22
  2. 92
  3. 40
  4. 84
  5. 5.1
  6. 27
  7. 37
  8. 7.4
  9. 33
  10. 32
  11. 5.4
  12. 9.2
  13. 51
  14. 44
  15. 7.3
  16. 5.9
  17. 6.1
  18. 30
  19. 32
  20. 26
  21. 4.7
  22. 63
  23. 29
  24. 7.7
  25. 5.5
  26. 8.8
  27. 7.1
  28. 7.6
  29. 37
  30. 55
  31. 26
  32. 53
  33. 46
  34. 23
  35. 7.9
  36. 4.9
  37. 29
  38. 6.5
  39. 9.6
  40. 18

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