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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 113 · 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): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  5. 5.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?
  6. 6.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?
  7. 7.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  8. 8.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  14. 14.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  15. 15.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  16. 16.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  20. 20.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  21. 21.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  22. 22.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  23. 23.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  24. 24.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?
  25. 25.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?
  26. 26.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  27. 27.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 2, 3 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.A leapfrog list starts 2, 7 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 363
  2. 484
  3. 407
  4. 649
  5. 583
  6. 308
  7. 429
  8. 594
  9. 473
  10. 825
  11. 902
  12. 550
  13. 319
  14. 528
  15. 726
  16. 759
  17. 616
  18. 517
  19. 495
  20. 913
  21. 847
  22. 374
  23. 803
  24. 671
  25. 253
  26. 616
  27. 649
  28. 924
  29. 869
  30. 363
  31. 1012
  32. 374
  33. 638
  34. 594
  35. 462
  36. 682
  37. 143
  38. 726
  39. 517
  40. 319

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