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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 168 · 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. 1.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  2. 2.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  3. 3.A leapfrog list starts 5, 7 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  9. 9.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  10. 10.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 8, 1 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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  14. 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  15. 15.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  17. 17.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  19. 19.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  20. 20.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  22. 22.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  26. 26.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?
  27. 27.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  36. 36.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  37. 37.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 1023
  2. 517
  3. 891
  4. 583
  5. 473
  6. 418
  7. 1111
  8. 594
  9. 759
  10. 737
  11. 561
  12. 528
  13. 759
  14. 143
  15. 1012
  16. 638
  17. 880
  18. 484
  19. 418
  20. 231
  21. 704
  22. 1034
  23. 847
  24. 429
  25. 814
  26. 1001
  27. 1199
  28. 858
  29. 682
  30. 1177
  31. 1287
  32. 1199
  33. 407
  34. 682
  35. 198
  36. 781
  37. 1034
  38. 649
  39. 836
  40. 583

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