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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 337 · 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. 1.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  3. 3.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  10. 10.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  11. 11.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  13. 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  14. 14.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  16. 16.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?
  17. 17.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  22. 22.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?
  23. 23.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  27. 27.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  28. 28.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  29. 29.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  30. 30.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?
  31. 31.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  36. 36.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?
  37. 37.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?
  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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =

Answer key

  1. 902
  2. 462
  3. 847
  4. 968
  5. 1199
  6. 363
  7. 1122
  8. 418
  9. 506
  10. 671
  11. 506
  12. 473
  13. 286
  14. 550
  15. 792
  16. 1232
  17. 506
  18. 935
  19. 286
  20. 539
  21. 363
  22. 1056
  23. 825
  24. 869
  25. 1012
  26. 913
  27. 682
  28. 418
  29. 484
  30. 583
  31. 682
  32. 616
  33. 1122
  34. 341
  35. 957
  36. 869
  37. 836
  38. 737
  39. 1287
  40. 814

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