← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 565 · 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 709 ÷ 31? (a) 240 (b) 24 (c) 2400
  2. 2.√30 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.4
  3. 3.√61 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.5 (d) 7.8
  4. 4.Best estimate of 4407 ÷ 67? (a) 630 (b) 63 (c) 6300
  5. 5.√32 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.4 (d) 5.5
  6. 6.Best estimate of 1074 ÷ 26? (a) 360 (b) 3600 (c) 36
  7. 7.Best estimate of 3042 ÷ 82? (a) 38 (b) 380 (c) 3800
  8. 8.Best estimate of 1172 ÷ 76? (a) 15 (b) 150 (c) 1500
  9. 9.Best estimate of 880 ÷ 24? (a) 440 (b) 4400 (c) 44
  10. 10.Best estimate of 2630 ÷ 63? (a) 440 (b) 44 (c) 4400
  11. 11.Best estimate of 1619 ÷ 26? (a) 540 (b) 5400 (c) 54
  12. 12.Best estimate of 2232 ÷ 31? (a) 7400 (b) 740 (c) 74
  13. 13.Best estimate of 3342 ÷ 41? (a) 8400 (b) 840 (c) 84
  14. 14.Best estimate of 568 ÷ 33? (a) 19 (b) 1900 (c) 190
  15. 15.√29 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.3 (d) 5.5
  16. 16.√43 to 1 decimal place? (a) 6.3 (b) 6.6 (c) 6.5 (d) 6.4
  17. 17.√94 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.7 (d) 9.8
  18. 18.√46 to 1 decimal place? (a) 6.7 (b) 7.0 (c) 6.8 (d) 6.9
  19. 19.√86 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.3 (d) 9.2
  20. 20.√27 to 1 decimal place? (a) 4.9 (b) 5.2 (c) 5.1 (d) 5.0
  21. 21.Best estimate of 6728 ÷ 84? (a) 84 (b) 840 (c) 8400
  22. 22.Best estimate of 4558 ÷ 48? (a) 910 (b) 9100 (c) 91
  23. 23.Best estimate of 6028 ÷ 64? (a) 10000 (b) 100 (c) 1000
  24. 24.√24 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 4.7
  25. 25.√50 to 1 decimal place? (a) 7.3 (b) 7.2 (c) 7.1 (d) 7.0
  26. 26.Best estimate of 4757 ÷ 82? (a) 5900 (b) 59 (c) 590
  27. 27.Best estimate of 3069 ÷ 48? (a) 610 (b) 6100 (c) 61
  28. 28.√20 to 1 decimal place? (a) 4.4 (b) 4.6 (c) 4.5 (d) 4.7
  29. 29.Best estimate of 4506 ÷ 52? (a) 90 (b) 900 (c) 9000
  30. 30.Best estimate of 1796 ÷ 87? (a) 2000 (b) 20 (c) 200
  31. 31.Best estimate of 1435 ÷ 26? (a) 480 (b) 4800 (c) 48
  32. 32.Best estimate of 2766 ÷ 46? (a) 5500 (b) 55 (c) 550
  33. 33.Best estimate of 4654 ÷ 72? (a) 6600 (b) 660 (c) 66
  34. 34.√85 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.4 (d) 9.3
  35. 35.Best estimate of 2178 ÷ 47? (a) 44 (b) 440 (c) 4400
  36. 36.√76 to 1 decimal place? (a) 8.8 (b) 8.5 (c) 8.7 (d) 8.6
  37. 37.Best estimate of 1593 ÷ 47? (a) 320 (b) 32 (c) 3200
  38. 38.Best estimate of 1970 ÷ 26? (a) 6600 (b) 66 (c) 660
  39. 39.Best estimate of 4020 ÷ 82? (a) 500 (b) 5000 (c) 50
  40. 40.Best estimate of 2477 ÷ 66? (a) 35 (b) 350 (c) 3500

Answer key

  1. 24
  2. 5.5
  3. 7.8
  4. 63
  5. 5.7
  6. 36
  7. 38
  8. 15
  9. 44
  10. 44
  11. 54
  12. 74
  13. 84
  14. 19
  15. 5.4
  16. 6.6
  17. 9.7
  18. 6.8
  19. 9.3
  20. 5.2
  21. 84
  22. 91
  23. 100
  24. 4.9
  25. 7.1
  26. 59
  27. 61
  28. 4.5
  29. 90
  30. 20
  31. 48
  32. 55
  33. 66
  34. 9.2
  35. 44
  36. 8.7
  37. 32
  38. 66
  39. 50
  40. 35

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths