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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 490 · 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.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  4. 4.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?
  5. 5.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  6. 6.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?
  7. 7.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  8. 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  9. 9.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?
  10. 10.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  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.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  13. 13.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  14. 14.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  15. 15.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  17. 17.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  18. 18.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  24. 24.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  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. 31.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  32. 32.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  35. 35.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =

Answer key

  1. 198
  2. 1111
  3. 418
  4. 1122
  5. 583
  6. 506
  7. 924
  8. 550
  9. 319
  10. 1067
  11. 528
  12. 638
  13. 451
  14. 902
  15. 1034
  16. 1111
  17. 341
  18. 693
  19. 605
  20. 429
  21. 506
  22. 781
  23. 495
  24. 1177
  25. 682
  26. 1056
  27. 671
  28. 858
  29. 671
  30. 935
  31. 484
  32. 308
  33. 462
  34. 759
  35. 968
  36. 1023
  37. 880
  38. 341
  39. 418
  40. 572

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