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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 137 · 40 questions
TalentJR

The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.

NameDateTime takenScore ___ / 40
  1. 1.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  2. 2.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  3. 3.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  4. 4.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  6. 6.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  8. 8.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  12. 12.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  13. 13.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  21. 21.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  22. 22.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  23. 23.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  25. 25.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  27. 27.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  28. 28.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  29. 29.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  30. 30.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  31. 31.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  33. 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  34. 34.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  38. 38.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  39. 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  40. 40.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =

Answer key

  1. 495
  2. 616
  3. 1111
  4. 308
  5. 704
  6. 880
  7. 583
  8. 825
  9. 341
  10. 572
  11. 528
  12. 1177
  13. 198
  14. 341
  15. 374
  16. 539
  17. 308
  18. 858
  19. 759
  20. 550
  21. 814
  22. 792
  23. 869
  24. 935
  25. 605
  26. 418
  27. 759
  28. 539
  29. 418
  30. 979
  31. 957
  32. 198
  33. 396
  34. 1199
  35. 231
  36. 308
  37. 594
  38. 781
  39. 517
  40. 1089

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