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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 559 · 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. 1.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  3. 3.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  4. 4.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?
  5. 5.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  7. 7.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  8. 8.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  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.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?
  11. 11.A leapfrog list starts 4, 8 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 7, 8 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): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  16. 16.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?
  17. 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  22. 22.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  23. 23.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  24. 24.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  26. 26.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  27. 27.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  28. 28.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  29. 29.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?
  30. 30.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  31. 31.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?
  32. 32.A leapfrog list starts 5, 5 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. 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.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?
  36. 36.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?
  37. 37.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?
  38. 38.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 407
  2. 341
  3. 825
  4. 231
  5. 693
  6. 594
  7. 924
  8. 429
  9. 704
  10. 484
  11. 924
  12. 1089
  13. 1111
  14. 308
  15. 671
  16. 1111
  17. 528
  18. 528
  19. 825
  20. 418
  21. 726
  22. 1089
  23. 1287
  24. 759
  25. 1012
  26. 1111
  27. 374
  28. 649
  29. 1232
  30. 638
  31. 319
  32. 715
  33. 517
  34. 429
  35. 847
  36. 594
  37. 198
  38. 539
  39. 286
  40. 363

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