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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 403 · 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.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  3. 3.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  4. 4.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  5. 5.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?
  6. 6.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  7. 7.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  8. 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  9. 9.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?
  10. 10.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  11. 11.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  19. 19.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  20. 20.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  24. 24.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  26. 26.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?
  27. 27.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?
  28. 28.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  29. 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  31. 31.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?
  32. 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  33. 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  34. 34.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  35. 35.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?
  36. 36.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  38. 38.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?
  39. 39.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =

Answer key

  1. 671
  2. 1199
  3. 484
  4. 561
  5. 737
  6. 671
  7. 638
  8. 594
  9. 407
  10. 924
  11. 1122
  12. 583
  13. 231
  14. 1012
  15. 319
  16. 902
  17. 737
  18. 935
  19. 759
  20. 418
  21. 847
  22. 671
  23. 671
  24. 539
  25. 319
  26. 781
  27. 1122
  28. 451
  29. 363
  30. 484
  31. 341
  32. 198
  33. 1111
  34. 539
  35. 341
  36. 847
  37. 1056
  38. 1111
  39. 803
  40. 803

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