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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 290 · 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): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  6. 6.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  7. 7.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  8. 8.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  9. 9.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  10. 10.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  13. 13.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  14. 14.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  19. 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  20. 20.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  25. 25.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?
  26. 26.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  28. 28.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.A leapfrog list starts 5, 2 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  31. 31.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  32. 32.A leapfrog list starts 5, 6 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 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  35. 35.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?
  36. 36.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?
  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. 38.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  39. 39.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 605
  2. 462
  3. 143
  4. 1144
  5. 1023
  6. 517
  7. 462
  8. 341
  9. 1034
  10. 374
  11. 682
  12. 902
  13. 616
  14. 1111
  15. 594
  16. 451
  17. 935
  18. 286
  19. 396
  20. 374
  21. 693
  22. 286
  23. 429
  24. 891
  25. 638
  26. 869
  27. 847
  28. 1232
  29. 451
  30. 869
  31. 451
  32. 803
  33. 1177
  34. 1199
  35. 253
  36. 759
  37. 473
  38. 649
  39. 1144
  40. 407

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