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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 76 · 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. 1.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  2. 2.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  4. 4.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  5. 5.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  8. 8.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  9. 9.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?
  10. 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  11. 11.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  12. 12.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?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  15. 15.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  21. 21.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?
  22. 22.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  23. 23.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  24. 24.A leapfrog list starts 9, 4 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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  29. 29.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?
  30. 30.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  35. 35.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  36. 36.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  37. 37.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?
  38. 38.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  40. 40.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 913
  2. 550
  3. 770
  4. 671
  5. 231
  6. 1111
  7. 528
  8. 726
  9. 1067
  10. 759
  11. 308
  12. 891
  13. 253
  14. 1177
  15. 1122
  16. 506
  17. 1287
  18. 539
  19. 1199
  20. 550
  21. 583
  22. 583
  23. 583
  24. 847
  25. 528
  26. 935
  27. 671
  28. 627
  29. 638
  30. 1056
  31. 495
  32. 880
  33. 759
  34. 319
  35. 528
  36. 638
  37. 869
  38. 341
  39. 429
  40. 715

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