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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 398 · 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.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?
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  3. 3.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  4. 4.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  5. 5.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  7. 7.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?
  8. 8.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  9. 9.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.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?
  12. 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  13. 13.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  14. 14.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?
  15. 15.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  23. 23.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  25. 25.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  30. 30.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  31. 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  32. 32.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  38. 38.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?
  39. 39.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?
  40. 40.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =

Answer key

  1. 1177
  2. 1067
  3. 539
  4. 473
  5. 506
  6. 231
  7. 649
  8. 583
  9. 704
  10. 1111
  11. 737
  12. 902
  13. 374
  14. 473
  15. 759
  16. 462
  17. 286
  18. 1287
  19. 726
  20. 583
  21. 484
  22. 726
  23. 770
  24. 913
  25. 638
  26. 869
  27. 638
  28. 231
  29. 847
  30. 627
  31. 924
  32. 715
  33. 374
  34. 1012
  35. 1199
  36. 627
  37. 495
  38. 451
  39. 759
  40. 319

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