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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 861 · 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 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  4. 4.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  5. 5.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?
  6. 6.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  8. 8.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  9. 9.A leapfrog list starts 4, 1 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 7, 5 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 1, 6 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, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  14. 14.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  15. 15.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?
  16. 16.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  17. 17.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?
  18. 18.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  19. 19.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  20. 20.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?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  24. 24.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?
  25. 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  26. 26.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?
  27. 27.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  28. 28.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  29. 29.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  31. 31.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  34. 34.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  35. 35.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?
  36. 36.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  37. 37.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  38. 38.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 979
  2. 968
  3. 407
  4. 979
  5. 594
  6. 1056
  7. 583
  8. 968
  9. 308
  10. 143
  11. 825
  12. 583
  13. 935
  14. 715
  15. 1089
  16. 572
  17. 693
  18. 924
  19. 341
  20. 572
  21. 374
  22. 1001
  23. 583
  24. 1067
  25. 814
  26. 715
  27. 1001
  28. 825
  29. 462
  30. 484
  31. 517
  32. 506
  33. 792
  34. 671
  35. 539
  36. 594
  37. 1034
  38. 847
  39. 836
  40. 198

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