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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 469 · 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  5. 5.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?
  6. 6.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?
  7. 7.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  13. 13.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?
  14. 14.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?
  15. 15.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  16. 16.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?
  17. 17.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?
  18. 18.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  19. 19.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  20. 20.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  23. 23.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  24. 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  25. 25.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  26. 26.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?
  27. 27.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  29. 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  30. 30.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  33. 33.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  34. 34.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  37. 37.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  38. 38.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?
  39. 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  40. 40.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =

Answer key

  1. 594
  2. 583
  3. 583
  4. 968
  5. 506
  6. 880
  7. 231
  8. 253
  9. 748
  10. 374
  11. 583
  12. 1067
  13. 572
  14. 671
  15. 748
  16. 517
  17. 143
  18. 429
  19. 660
  20. 814
  21. 341
  22. 726
  23. 506
  24. 671
  25. 891
  26. 616
  27. 1023
  28. 308
  29. 594
  30. 869
  31. 616
  32. 539
  33. 924
  34. 539
  35. 528
  36. 880
  37. 979
  38. 682
  39. 561
  40. 1287

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