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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 794 · 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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  5. 5.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 1, 7 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): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  9. 9.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  10. 10.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?
  11. 11.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?
  12. 12.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  13. 13.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  19. 19.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  20. 20.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  21. 21.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.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?
  24. 24.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  25. 25.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  32. 32.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  39. 39.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?
  40. 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =

Answer key

  1. 671
  2. 594
  3. 363
  4. 1012
  5. 858
  6. 1001
  7. 671
  8. 1023
  9. 858
  10. 495
  11. 638
  12. 649
  13. 473
  14. 1177
  15. 825
  16. 1199
  17. 1023
  18. 374
  19. 913
  20. 308
  21. 770
  22. 231
  23. 814
  24. 363
  25. 759
  26. 803
  27. 506
  28. 759
  29. 770
  30. 451
  31. 451
  32. 638
  33. 418
  34. 561
  35. 374
  36. 1012
  37. 759
  38. 429
  39. 649
  40. 198

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