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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 866 · 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. 1.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  2. 2.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?
  3. 3.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  4. 4.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?
  5. 5.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  10. 10.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  11. 11.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?
  12. 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  13. 13.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?
  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. 15.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  16. 16.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  19. 19.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  26. 26.A leapfrog list starts 1, 3 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 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  30. 30.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  31. 31.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  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. 33.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  34. 34.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  35. 35.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  36. 36.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?
  37. 37.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  40. 40.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =

Answer key

  1. 429
  2. 902
  3. 693
  4. 539
  5. 1089
  6. 924
  7. 231
  8. 704
  9. 451
  10. 1144
  11. 528
  12. 506
  13. 1012
  14. 341
  15. 704
  16. 891
  17. 660
  18. 627
  19. 638
  20. 726
  21. 836
  22. 1023
  23. 1287
  24. 286
  25. 924
  26. 319
  27. 748
  28. 660
  29. 583
  30. 803
  31. 660
  32. 561
  33. 374
  34. 583
  35. 396
  36. 1012
  37. 1067
  38. 462
  39. 979
  40. 880

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