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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 773 · 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, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  2. 2.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?
  3. 3.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  4. 4.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  5. 5.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  6. 6.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 9, 9 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, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  12. 12.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  14. 14.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  15. 15.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  16. 16.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?
  17. 17.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  22. 22.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  23. 23.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  27. 27.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  31. 31.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  32. 32.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  33. 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  34. 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 9, 3 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 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 759
  2. 638
  3. 341
  4. 671
  5. 803
  6. 594
  7. 605
  8. 583
  9. 550
  10. 1287
  11. 1287
  12. 649
  13. 869
  14. 924
  15. 660
  16. 396
  17. 484
  18. 418
  19. 1023
  20. 253
  21. 847
  22. 770
  23. 638
  24. 583
  25. 1067
  26. 308
  27. 1056
  28. 737
  29. 957
  30. 880
  31. 550
  32. 858
  33. 495
  34. 792
  35. 429
  36. 759
  37. 473
  38. 231
  39. 1111
  40. 473

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