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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 218 · 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. 1.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  2. 2.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  5. 5.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?
  6. 6.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  9. 9.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  17. 17.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  18. 18.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?
  19. 19.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  21. 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  22. 22.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  23. 23.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  24. 24.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?
  25. 25.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  26. 26.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?
  27. 27.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  29. 29.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  30. 30.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  31. 31.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  32. 32.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?
  33. 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  34. 34.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  35. 35.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?
  36. 36.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?
  37. 37.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  38. 38.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 627
  2. 847
  3. 693
  4. 649
  5. 583
  6. 781
  7. 594
  8. 847
  9. 374
  10. 605
  11. 1144
  12. 407
  13. 902
  14. 341
  15. 418
  16. 1023
  17. 1111
  18. 748
  19. 1122
  20. 1122
  21. 550
  22. 935
  23. 231
  24. 517
  25. 1012
  26. 341
  27. 528
  28. 880
  29. 825
  30. 198
  31. 583
  32. 561
  33. 396
  34. 429
  35. 407
  36. 627
  37. 781
  38. 737
  39. 583
  40. 836

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