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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 618 · 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): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  4. 4.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.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?
  11. 11.A leapfrog list starts 9, 1 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, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  16. 16.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  17. 17.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  18. 18.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  19. 19.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?
  20. 20.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?
  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.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?
  23. 23.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  24. 24.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?
  25. 25.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  26. 26.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  27. 27.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  28. 28.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  29. 29.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?
  30. 30.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?
  31. 31.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  32. 32.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  33. 33.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  34. 34.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 407
  2. 572
  3. 814
  4. 1232
  5. 550
  6. 506
  7. 957
  8. 880
  9. 363
  10. 616
  11. 583
  12. 143
  13. 1067
  14. 781
  15. 495
  16. 594
  17. 649
  18. 528
  19. 594
  20. 605
  21. 836
  22. 649
  23. 1144
  24. 143
  25. 462
  26. 803
  27. 1122
  28. 473
  29. 726
  30. 935
  31. 341
  32. 869
  33. 1023
  34. 1034
  35. 231
  36. 671
  37. 583
  38. 473
  39. 561
  40. 473

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