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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 454 · 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): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  2. 2.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  5. 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  6. 6.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  7. 7.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  8. 8.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  15. 15.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?
  16. 16.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?
  17. 17.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  19. 19.A leapfrog list starts 3, 3 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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  21. 21.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  22. 22.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  23. 23.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?
  24. 24.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  25. 25.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  31. 31.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?
  32. 32.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?

Answer key

  1. 814
  2. 935
  3. 1122
  4. 715
  5. 902
  6. 418
  7. 605
  8. 759
  9. 308
  10. 462
  11. 1067
  12. 880
  13. 517
  14. 484
  15. 616
  16. 363
  17. 594
  18. 726
  19. 429
  20. 484
  21. 1144
  22. 781
  23. 902
  24. 363
  25. 792
  26. 1177
  27. 957
  28. 880
  29. 671
  30. 847
  31. 506
  32. 407
  33. 396
  34. 429
  35. 583
  36. 1012
  37. 319
  38. 869
  39. 946
  40. 847

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