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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 414 · 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. 1.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  2. 2.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  6. 6.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  7. 7.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?
  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.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?
  10. 10.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  12. 12.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?
  13. 13.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  14. 14.A leapfrog list starts 5, 9 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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  16. 16.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?
  17. 17.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  19. 19.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?
  20. 20.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  27. 27.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?
  28. 28.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?
  29. 29.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  31. 31.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  33. 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  34. 34.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  36. 36.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  37. 37.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?
  38. 38.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  39. 39.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?
  40. 40.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =

Answer key

  1. 979
  2. 814
  3. 341
  4. 858
  5. 1122
  6. 495
  7. 539
  8. 704
  9. 319
  10. 1122
  11. 649
  12. 451
  13. 143
  14. 1067
  15. 759
  16. 198
  17. 803
  18. 1111
  19. 638
  20. 957
  21. 803
  22. 396
  23. 979
  24. 759
  25. 649
  26. 968
  27. 1001
  28. 759
  29. 605
  30. 506
  31. 869
  32. 924
  33. 418
  34. 396
  35. 286
  36. 1023
  37. 517
  38. 759
  39. 418
  40. 836

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