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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 392 · 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. 1.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  2. 2.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  5. 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  8. 8.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  12. 12.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  14. 14.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  15. 15.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  17. 17.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  18. 18.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  19. 19.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  21. 21.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  22. 22.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?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  25. 25.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  26. 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  27. 27.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  28. 28.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  29. 29.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  30. 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  31. 31.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 495
  2. 286
  3. 396
  4. 1034
  5. 451
  6. 583
  7. 616
  8. 517
  9. 286
  10. 627
  11. 638
  12. 473
  13. 286
  14. 473
  15. 1232
  16. 748
  17. 374
  18. 1177
  19. 1012
  20. 1232
  21. 957
  22. 528
  23. 517
  24. 451
  25. 143
  26. 583
  27. 935
  28. 792
  29. 308
  30. 836
  31. 891
  32. 946
  33. 869
  34. 539
  35. 429
  36. 682
  37. 561
  38. 704
  39. 781
  40. 319

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