← Number puzzles and digit counting lesson New set →

Number Puzzles Worksheet for Maths Olympiad

Maths Olympiad topic 25: Number puzzles and digit counting · Set 965 · 40 questions
TalentJR

How to solve it (Count place by place): Count a digit place by place: first in the ones place, then in the tens place (a number like 33 counts twice). Page numbers: pages 1–9 use 1 digit each, 10–99 use 2, 100–999 use 3. A 3 × 3 magic square made of nine numbers: each row adds up to (sum of all nine) ÷ 3.

NameDateTime takenScore ___ / 40
  1. 1.The numbers 1 to 9 are placed in a 3 × 3 magic square, so every row, column and diagonal has the same sum. What is that sum? (a) 45 (b) 15 (c) 5 (d) 18
  2. 2.The numbers 4 to 12 are placed in a 3 × 3 magic square, so every row, column and diagonal has the same sum. What is that sum? (a) 27 (b) 8 (c) 72 (d) 24
  3. 3.How many two-digit numbers have digits that add up to 3? (a) 2 (b) 10 (c) 4 (d) 3
  4. 4.How many times is the digit 3 written when you write all the numbers from 1 to 88? (a) 20 (b) 18 (c) 8 (d) 19
  5. 5.A book has 240 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 603 (b) 612 (c) 480 (d) 613
  6. 6.How many times is the digit 6 written when you write all the numbers from 1 to 36? (a) 3 (b) 5 (c) 2 (d) 4
  7. 7.How many two-digit numbers have digits that add up to 2? (a) 3 (b) 1 (c) 10 (d) 2
  8. 8.A book has 250 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 642 (b) 643 (c) 633 (d) 500
  9. 9.How many times is the digit 9 written when you write all the numbers from 1 to 80? (a) 6 (b) 7 (c) 8 (d) 9
  10. 10.The numbers 11 to 19 are placed in a 3 × 3 magic square, so every row, column and diagonal has the same sum. What is that sum? (a) 135 (b) 48 (c) 15 (d) 45
  11. 11.How many times is the digit 7 written when you write all the numbers from 1 to 46? (a) 5 (b) 4 (c) 3 (d) 2
  12. 12.A book has 36 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 64 (b) 54 (c) 72 (d) 63
  13. 13.How many times is the digit 4 written when you write all the numbers from 1 to 47? (a) 14 (b) 13 (c) 12 (d) 4
  14. 14.How many times is the digit 4 written when you write all the numbers from 1 to 38? (a) 3 (b) 2 (c) 5 (d) 4
  15. 15.How many two-digit numbers have digits that add up to 13? (a) 6 (b) 5 (c) 7 (d) 14
  16. 16.How many two-digit numbers have digits that add up to 8? (a) 10 (b) 9 (c) 8 (d) 7
  17. 17.A book has 194 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 474 (b) 465 (c) 388 (d) 475
  18. 18.How many two-digit numbers have digits that add up to 11? (a) 7 (b) 9 (c) 12 (d) 8
  19. 19.The numbers 17 to 25 are placed in a 3 × 3 magic square, so every row, column and diagonal has the same sum. What is that sum? (a) 21 (b) 63 (c) 189 (d) 66
  20. 20.How many two-digit numbers have digits that add up to 5? (a) 4 (b) 5 (c) 6 (d) 10
  21. 21.The numbers 10 to 18 are placed in a 3 × 3 magic square, so every row, column and diagonal has the same sum. What is that sum? (a) 14 (b) 42 (c) 126 (d) 45
  22. 22.A book has 47 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 85 (b) 86 (c) 76 (d) 94
  23. 23.How many times is the digit 7 written when you write all the numbers from 1 to 57? (a) 6 (b) 5 (c) 4 (d) 7
  24. 24.A book has 199 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 398 (b) 490 (c) 480 (d) 489
  25. 25.A book has 232 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 464 (b) 589 (c) 579 (d) 588
  26. 26.A book has 64 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 110 (b) 120 (c) 128 (d) 119
  27. 27.How many times is the digit 7 written when you write all the numbers from 1 to 48? (a) 4 (b) 5 (c) 6 (d) 3
  28. 28.How many times is the digit 2 written when you write all the numbers from 1 to 66? (a) 16 (b) 6 (c) 17 (d) 18
  29. 29.A book has 21 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 24 (b) 33 (c) 42 (d) 34
  30. 30.How many times is the digit 1 written when you write all the numbers from 1 to 71? (a) 17 (b) 7 (c) 18 (d) 19
  31. 31.A book has 200 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 400 (b) 492 (c) 483 (d) 493
  32. 32.The numbers 9 to 17 are placed in a 3 × 3 magic square, so every row, column and diagonal has the same sum. What is that sum? (a) 39 (b) 42 (c) 13 (d) 117
  33. 33.How many times is the digit 4 written when you write all the numbers from 1 to 44? (a) 4 (b) 10 (c) 9 (d) 11
  34. 34.How many times is the digit 2 written when you write all the numbers from 1 to 46? (a) 15 (b) 16 (c) 4 (d) 14
  35. 35.How many two-digit numbers have digits that add up to 14? (a) 4 (b) 15 (c) 5 (d) 6
  36. 36.How many times is the digit 3 written when you write all the numbers from 1 to 35? (a) 10 (b) 11 (c) 9 (d) 3
  37. 37.How many times is the digit 9 written when you write all the numbers from 1 to 92? (a) 10 (b) 13 (c) 12 (d) 9
  38. 38.How many times is the digit 9 written when you write all the numbers from 1 to 72? (a) 6 (b) 7 (c) 5 (d) 8
  39. 39.A book has 90 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 180 (b) 171 (c) 172 (d) 162
  40. 40.A book has 44 pages, numbered 1, 2, 3 and so on. How many digits are printed to number all the pages? (a) 70 (b) 88 (c) 80 (d) 79

Answer key

  1. 15
  2. 24
  3. 3
  4. 19
  5. 612
  6. 4
  7. 2
  8. 642
  9. 8
  10. 45
  11. 4
  12. 63
  13. 13
  14. 4
  15. 6
  16. 8
  17. 474
  18. 8
  19. 63
  20. 5
  21. 42
  22. 85
  23. 6
  24. 489
  25. 588
  26. 119
  27. 5
  28. 17
  29. 33
  30. 18
  31. 492
  32. 39
  33. 10
  34. 15
  35. 5
  36. 10
  37. 12
  38. 7
  39. 171
  40. 79

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