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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 572 · 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. 1.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  2. 2.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?
  3. 3.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?
  4. 4.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  5. 5.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  6. 6.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 1, 7 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 8, 7 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, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  12. 12.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  13. 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  14. 14.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  16. 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  17. 17.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?
  18. 18.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?
  19. 19.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  20. 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  21. 21.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?
  22. 22.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  24. 24.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  31. 31.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  32. 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  33. 33.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  37. 37.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  38. 38.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?
  39. 39.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?

Answer key

  1. 814
  2. 231
  3. 429
  4. 495
  5. 737
  6. 979
  7. 528
  8. 1023
  9. 671
  10. 1056
  11. 935
  12. 517
  13. 726
  14. 1199
  15. 1199
  16. 231
  17. 143
  18. 198
  19. 1232
  20. 660
  21. 869
  22. 968
  23. 583
  24. 495
  25. 1089
  26. 517
  27. 1144
  28. 319
  29. 847
  30. 781
  31. 396
  32. 198
  33. 704
  34. 506
  35. 407
  36. 693
  37. 484
  38. 858
  39. 1287
  40. 1023

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