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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 835 · 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 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  2. 2.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?
  3. 3.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.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?
  6. 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  7. 7.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  9. 9.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  10. 10.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?
  11. 11.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?
  12. 12.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  13. 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  16. 16.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  17. 17.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  21. 21.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  22. 22.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?
  23. 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  26. 26.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  27. 27.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  28. 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  35. 35.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?
  36. 36.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  40. 40.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =

Answer key

  1. 1089
  2. 517
  3. 748
  4. 594
  5. 374
  6. 616
  7. 803
  8. 704
  9. 1199
  10. 253
  11. 1111
  12. 1144
  13. 726
  14. 1023
  15. 451
  16. 968
  17. 1144
  18. 506
  19. 1232
  20. 759
  21. 671
  22. 528
  23. 363
  24. 770
  25. 814
  26. 638
  27. 748
  28. 814
  29. 1034
  30. 253
  31. 583
  32. 319
  33. 902
  34. 1056
  35. 143
  36. 1199
  37. 924
  38. 682
  39. 803
  40. 627

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