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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 707 · 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 2528 ÷ 69? (a) 36 (b) 360 (c) 3600
  2. 2.√96 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.9 (d) 9.7
  3. 3.Best estimate of 1860 ÷ 62? (a) 31 (b) 3100 (c) 310
  4. 4.Best estimate of 8072 ÷ 86? (a) 900 (b) 90 (c) 9000
  5. 5.Best estimate of 4897 ÷ 68? (a) 7000 (b) 700 (c) 70
  6. 6.Best estimate of 1250 ÷ 32? (a) 4200 (b) 42 (c) 420
  7. 7.√85 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.5 (d) 9.3
  8. 8.√63 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.0 (d) 8.1
  9. 9.√38 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  10. 10.Best estimate of 1963 ÷ 84? (a) 25 (b) 2500 (c) 250
  11. 11.√55 to 1 decimal place? (a) 7.3 (b) 7.1 (c) 7.4 (d) 7.2
  12. 12.√52 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.2
  13. 13.√56 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.6 (d) 7.8
  14. 14.√42 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.7 (d) 6.4
  15. 15.√26 to 1 decimal place? (a) 4.8 (b) 5.1 (c) 5.0 (d) 4.9
  16. 16.Best estimate of 2528 ÷ 31? (a) 8400 (b) 840 (c) 84
  17. 17.Best estimate of 5327 ÷ 56? (a) 89 (b) 8900 (c) 890
  18. 18.√43 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.6 (d) 6.4
  19. 19.Best estimate of 3810 ÷ 77? (a) 4800 (b) 48 (c) 480
  20. 20.Best estimate of 6957 ÷ 79? (a) 8700 (b) 87 (c) 870
  21. 21.Best estimate of 974 ÷ 44? (a) 240 (b) 24 (c) 2400
  22. 22.Best estimate of 3207 ÷ 56? (a) 53 (b) 530 (c) 5300
  23. 23.Best estimate of 872 ÷ 42? (a) 2200 (b) 22 (c) 220
  24. 24.Best estimate of 2487 ÷ 46? (a) 500 (b) 5000 (c) 50
  25. 25.Best estimate of 2451 ÷ 48? (a) 4900 (b) 490 (c) 49
  26. 26.Best estimate of 2600 ÷ 49? (a) 5200 (b) 520 (c) 52
  27. 27.Best estimate of 820 ÷ 63? (a) 14 (b) 140 (c) 1400
  28. 28.Best estimate of 1103 ÷ 22? (a) 550 (b) 5500 (c) 55
  29. 29.√34 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 5.7
  30. 30.Best estimate of 3225 ÷ 37? (a) 810 (b) 81 (c) 8100
  31. 31.Best estimate of 1026 ÷ 36? (a) 260 (b) 26 (c) 2600
  32. 32.Best estimate of 1406 ÷ 76? (a) 1800 (b) 180 (c) 18
  33. 33.Best estimate of 3183 ÷ 66? (a) 450 (b) 4500 (c) 45
  34. 34.√48 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.9 (d) 7.0
  35. 35.Best estimate of 1606 ÷ 33? (a) 5400 (b) 540 (c) 54
  36. 36.√71 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.7
  37. 37.Best estimate of 3448 ÷ 52? (a) 690 (b) 6900 (c) 69
  38. 38.Best estimate of 1610 ÷ 46? (a) 3200 (b) 320 (c) 32
  39. 39.√40 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.4 (d) 6.1
  40. 40.Best estimate of 2918 ÷ 37? (a) 730 (b) 7300 (c) 73

Answer key

  1. 36
  2. 9.8
  3. 31
  4. 90
  5. 70
  6. 42
  7. 9.2
  8. 7.9
  9. 6.2
  10. 25
  11. 7.4
  12. 7.2
  13. 7.5
  14. 6.5
  15. 5.1
  16. 84
  17. 89
  18. 6.6
  19. 48
  20. 87
  21. 24
  22. 53
  23. 22
  24. 50
  25. 49
  26. 52
  27. 14
  28. 55
  29. 5.8
  30. 81
  31. 26
  32. 18
  33. 45
  34. 6.9
  35. 54
  36. 8.4
  37. 69
  38. 32
  39. 6.3
  40. 73

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