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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 981 · 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 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  3. 3.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  4. 4.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  5. 5.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 8, 2 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  10. 10.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  12. 12.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?
  13. 13.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  14. 14.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?
  15. 15.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  19. 19.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?
  20. 20.A leapfrog list starts 4, 8 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, 1 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, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  23. 23.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  24. 24.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  26. 26.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  27. 27.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?
  28. 28.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  33. 33.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?
  34. 34.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  35. 35.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  36. 36.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?
  37. 37.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?
  38. 38.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  40. 40.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?

Answer key

  1. 374
  2. 803
  3. 1177
  4. 341
  5. 814
  6. 143
  7. 616
  8. 935
  9. 1034
  10. 308
  11. 979
  12. 638
  13. 484
  14. 693
  15. 759
  16. 891
  17. 880
  18. 847
  19. 198
  20. 924
  21. 253
  22. 286
  23. 583
  24. 1067
  25. 341
  26. 957
  27. 627
  28. 836
  29. 517
  30. 396
  31. 979
  32. 561
  33. 550
  34. 946
  35. 693
  36. 693
  37. 583
  38. 649
  39. 1199
  40. 1089

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