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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 614 · 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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  8. 8.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  9. 9.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 9, 2 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  13. 13.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  18. 18.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?
  19. 19.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?
  20. 20.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  25. 25.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  26. 26.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  29. 29.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  30. 30.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  33. 33.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  36. 36.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  37. 37.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  38. 38.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?
  39. 39.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  40. 40.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =

Answer key

  1. 1232
  2. 341
  3. 1056
  4. 726
  5. 803
  6. 594
  7. 1199
  8. 517
  9. 649
  10. 671
  11. 341
  12. 143
  13. 1001
  14. 418
  15. 1056
  16. 451
  17. 396
  18. 561
  19. 495
  20. 1122
  21. 1023
  22. 880
  23. 649
  24. 1287
  25. 924
  26. 517
  27. 935
  28. 418
  29. 583
  30. 363
  31. 473
  32. 869
  33. 660
  34. 429
  35. 517
  36. 1199
  37. 682
  38. 1012
  39. 550
  40. 814

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