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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 687 · 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.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  3. 3.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  5. 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  6. 6.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?
  7. 7.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  8. 8.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  9. 9.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  11. 11.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 7, 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 7, 2 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 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  19. 19.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  20. 20.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?
  21. 21.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  22. 22.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  23. 23.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?
  24. 24.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  26. 26.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  27. 27.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?
  28. 28.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?
  29. 29.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  31. 31.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =

Answer key

  1. 286
  2. 605
  3. 792
  4. 847
  5. 616
  6. 594
  7. 748
  8. 286
  9. 429
  10. 836
  11. 462
  12. 484
  13. 583
  14. 913
  15. 583
  16. 561
  17. 253
  18. 638
  19. 429
  20. 495
  21. 572
  22. 418
  23. 253
  24. 308
  25. 594
  26. 231
  27. 682
  28. 605
  29. 803
  30. 473
  31. 1144
  32. 572
  33. 759
  34. 814
  35. 924
  36. 231
  37. 506
  38. 803
  39. 616
  40. 363

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