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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 583 · 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): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  2. 2.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  4. 4.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?
  5. 5.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  6. 6.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  9. 9.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  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. 11.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  12. 12.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  18. 18.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?
  19. 19.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  22. 22.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  23. 23.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?
  24. 24.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  27. 27.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  29. 29.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  30. 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  31. 31.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  33. 33.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  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.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =

Answer key

  1. 539
  2. 451
  3. 1177
  4. 704
  5. 473
  6. 1001
  7. 902
  8. 1034
  9. 517
  10. 572
  11. 704
  12. 495
  13. 946
  14. 374
  15. 561
  16. 605
  17. 506
  18. 528
  19. 704
  20. 682
  21. 517
  22. 825
  23. 308
  24. 539
  25. 407
  26. 957
  27. 1089
  28. 638
  29. 1199
  30. 1067
  31. 1122
  32. 1111
  33. 616
  34. 1199
  35. 528
  36. 363
  37. 319
  38. 1089
  39. 594
  40. 979

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