← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 909 · 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 2655 ÷ 34? (a) 890 (b) 8900 (c) 89
  2. 2.√46 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 6.6
  3. 3.Best estimate of 4150 ÷ 57? (a) 690 (b) 6900 (c) 69
  4. 4.√37 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.2 (d) 6.3
  5. 5.√62 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.0 (d) 7.7
  6. 6.√76 to 1 decimal place? (a) 8.7 (b) 8.4 (c) 8.6 (d) 8.5
  7. 7.Best estimate of 2046 ÷ 34? (a) 6800 (b) 680 (c) 68
  8. 8.√22 to 1 decimal place? (a) 4.4 (b) 4.7 (c) 4.6 (d) 4.5
  9. 9.√21 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.7 (d) 4.6
  10. 10.Best estimate of 7056 ÷ 87? (a) 780 (b) 7800 (c) 78
  11. 11.√72 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.4 (d) 8.5
  12. 12.√41 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.4
  13. 13.Best estimate of 1334 ÷ 77? (a) 170 (b) 17 (c) 1700
  14. 14.√51 to 1 decimal place? (a) 6.9 (b) 7.2 (c) 7.0 (d) 7.1
  15. 15.Best estimate of 2579 ÷ 33? (a) 860 (b) 8600 (c) 86
  16. 16.√75 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.7 (d) 8.4
  17. 17.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  18. 18.√61 to 1 decimal place? (a) 7.6 (b) 7.9 (c) 7.7 (d) 7.8
  19. 19.√20 to 1 decimal place? (a) 4.4 (b) 4.6 (c) 4.3 (d) 4.5
  20. 20.Best estimate of 6636 ÷ 79? (a) 8300 (b) 830 (c) 83
  21. 21.√96 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.9 (d) 9.8
  22. 22.Best estimate of 3403 ÷ 44? (a) 850 (b) 8500 (c) 85
  23. 23.√74 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.3 (d) 8.4
  24. 24.√67 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.4 (d) 8.3
  25. 25.Best estimate of 4523 ÷ 77? (a) 57 (b) 570 (c) 5700
  26. 26.Best estimate of 3547 ÷ 78? (a) 44 (b) 440 (c) 4400
  27. 27.Best estimate of 3706 ÷ 59? (a) 6200 (b) 620 (c) 62
  28. 28.Best estimate of 2026 ÷ 49? (a) 4100 (b) 41 (c) 410
  29. 29.Best estimate of 753 ÷ 26? (a) 250 (b) 25 (c) 2500
  30. 30.Best estimate of 1606 ÷ 46? (a) 32 (b) 3200 (c) 320
  31. 31.Best estimate of 2743 ÷ 29? (a) 9100 (b) 910 (c) 91
  32. 32.Best estimate of 2174 ÷ 72? (a) 31 (b) 310 (c) 3100
  33. 33.√30 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.4 (d) 5.7
  34. 34.Best estimate of 3440 ÷ 41? (a) 860 (b) 86 (c) 8600
  35. 35.Best estimate of 4720 ÷ 67? (a) 670 (b) 67 (c) 6700
  36. 36.√58 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.7 (d) 7.9
  37. 37.Best estimate of 1924 ÷ 38? (a) 4800 (b) 480 (c) 48
  38. 38.Best estimate of 447 ÷ 26? (a) 1500 (b) 15 (c) 150
  39. 39.√66 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.0 (d) 7.9
  40. 40.Best estimate of 2806 ÷ 31? (a) 94 (b) 9400 (c) 940

Answer key

  1. 89
  2. 6.8
  3. 69
  4. 6.1
  5. 7.9
  6. 8.7
  7. 68
  8. 4.7
  9. 4.6
  10. 78
  11. 8.5
  12. 6.4
  13. 17
  14. 7.1
  15. 86
  16. 8.7
  17. 6.3
  18. 7.8
  19. 4.5
  20. 83
  21. 9.8
  22. 85
  23. 8.6
  24. 8.2
  25. 57
  26. 44
  27. 62
  28. 41
  29. 25
  30. 32
  31. 91
  32. 31
  33. 5.5
  34. 86
  35. 67
  36. 7.6
  37. 48
  38. 15
  39. 8.1
  40. 94

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