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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 156 · 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. 1.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  2. 2.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  4. 4.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?
  5. 5.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  6. 6.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?
  7. 7.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  8. 8.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  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, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  20. 20.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?
  21. 21.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  23. 23.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  25. 25.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?
  26. 26.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  27. 27.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?
  28. 28.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  29. 29.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  30. 30.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  31. 31.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  32. 32.A leapfrog list starts 2, 4 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  34. 34.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?
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  38. 38.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?
  39. 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  40. 40.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?

Answer key

  1. 429
  2. 308
  3. 979
  4. 1177
  5. 1012
  6. 704
  7. 539
  8. 825
  9. 1001
  10. 495
  11. 814
  12. 737
  13. 341
  14. 737
  15. 253
  16. 924
  17. 759
  18. 1144
  19. 913
  20. 1001
  21. 1067
  22. 682
  23. 143
  24. 737
  25. 286
  26. 924
  27. 759
  28. 473
  29. 1023
  30. 517
  31. 825
  32. 462
  33. 1122
  34. 407
  35. 231
  36. 363
  37. 847
  38. 583
  39. 583
  40. 594

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