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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 231 · 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 6, 6 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, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  8. 8.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  9. 9.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  11. 11.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  12. 12.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  13. 13.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  14. 14.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  15. 15.A leapfrog list starts 9, 6 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 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.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?
  19. 19.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  20. 20.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  21. 21.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  22. 22.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  23. 23.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?
  24. 24.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  25. 25.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  26. 26.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  28. 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  33. 33.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  34. 34.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  35. 35.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  37. 37.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  38. 38.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?
  39. 39.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  40. 40.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?

Answer key

  1. 858
  2. 451
  3. 693
  4. 143
  5. 1034
  6. 583
  7. 473
  8. 803
  9. 957
  10. 473
  11. 231
  12. 616
  13. 1199
  14. 792
  15. 1023
  16. 550
  17. 517
  18. 638
  19. 847
  20. 462
  21. 1232
  22. 847
  23. 594
  24. 594
  25. 1122
  26. 583
  27. 1012
  28. 902
  29. 935
  30. 1089
  31. 671
  32. 880
  33. 374
  34. 143
  35. 1001
  36. 715
  37. 418
  38. 935
  39. 550
  40. 253

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