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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 295 · 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): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  2. 2.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  3. 3.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  5. 5.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  8. 8.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?
  9. 9.A leapfrog list starts 8, 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  12. 12.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  14. 14.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  15. 15.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  17. 17.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  18. 18.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?
  19. 19.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  26. 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  27. 27.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  28. 28.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  32. 32.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  34. 34.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?
  35. 35.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  40. 40.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?

Answer key

  1. 649
  2. 484
  3. 374
  4. 858
  5. 374
  6. 1089
  7. 891
  8. 363
  9. 704
  10. 935
  11. 814
  12. 957
  13. 869
  14. 1111
  15. 1177
  16. 253
  17. 726
  18. 286
  19. 770
  20. 286
  21. 253
  22. 946
  23. 616
  24. 671
  25. 781
  26. 935
  27. 1199
  28. 814
  29. 572
  30. 627
  31. 693
  32. 704
  33. 429
  34. 517
  35. 1144
  36. 1067
  37. 561
  38. 649
  39. 1122
  40. 836

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