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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 707 · 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. 1.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  3. 3.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?
  4. 4.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  5. 5.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?
  6. 6.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  7. 7.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  9. 9.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?
  10. 10.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?
  11. 11.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  13. 13.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  16. 16.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  18. 18.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?
  19. 19.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?
  20. 20.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  21. 21.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?
  22. 22.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?
  23. 23.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  24. 24.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  25. 25.A leapfrog list starts 8, 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): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  29. 29.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?
  30. 30.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?
  31. 31.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  32. 32.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?
  33. 33.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?
  34. 34.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  35. 35.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  38. 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  39. 39.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  40. 40.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?

Answer key

  1. 649
  2. 539
  3. 572
  4. 770
  5. 396
  6. 418
  7. 638
  8. 1177
  9. 814
  10. 847
  11. 627
  12. 847
  13. 847
  14. 473
  15. 715
  16. 671
  17. 671
  18. 429
  19. 231
  20. 1023
  21. 781
  22. 253
  23. 539
  24. 319
  25. 1232
  26. 880
  27. 429
  28. 198
  29. 253
  30. 286
  31. 341
  32. 671
  33. 836
  34. 1034
  35. 407
  36. 858
  37. 1144
  38. 451
  39. 1111
  40. 869

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