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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 783 · 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  3. 3.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?
  4. 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  5. 5.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?
  6. 6.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  9. 9.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  12. 12.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?
  13. 13.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  14. 14.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?
  15. 15.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  16. 16.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  20. 20.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.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?
  22. 22.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?
  23. 23.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.A leapfrog list starts 2, 1 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, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  26. 26.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?
  27. 27.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  28. 28.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  29. 29.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?
  30. 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  31. 31.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  32. 32.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  34. 34.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?
  35. 35.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?
  36. 36.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  37. 37.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  39. 39.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?
  40. 40.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =

Answer key

  1. 550
  2. 671
  3. 462
  4. 836
  5. 198
  6. 638
  7. 1034
  8. 539
  9. 231
  10. 407
  11. 946
  12. 1287
  13. 847
  14. 583
  15. 594
  16. 143
  17. 957
  18. 913
  19. 649
  20. 418
  21. 1144
  22. 495
  23. 583
  24. 198
  25. 561
  26. 594
  27. 1287
  28. 880
  29. 528
  30. 484
  31. 1144
  32. 1089
  33. 781
  34. 583
  35. 880
  36. 583
  37. 1177
  38. 308
  39. 484
  40. 286

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