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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 196 · 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. 1.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.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?
  8. 8.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?
  9. 9.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  10. 10.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  11. 11.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  16. 16.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  17. 17.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?
  18. 18.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?
  19. 19.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  20. 20.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  21. 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  24. 24.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  26. 26.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?
  27. 27.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  28. 28.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?
  29. 29.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  30. 30.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  33. 33.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  34. 34.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?
  35. 35.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  36. 36.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?
  37. 37.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  40. 40.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =

Answer key

  1. 319
  2. 462
  3. 1012
  4. 253
  5. 616
  6. 814
  7. 1287
  8. 737
  9. 1232
  10. 1144
  11. 935
  12. 1067
  13. 1056
  14. 319
  15. 649
  16. 517
  17. 550
  18. 957
  19. 682
  20. 726
  21. 605
  22. 319
  23. 418
  24. 1199
  25. 572
  26. 143
  27. 803
  28. 627
  29. 902
  30. 253
  31. 671
  32. 561
  33. 484
  34. 616
  35. 891
  36. 847
  37. 726
  38. 869
  39. 759
  40. 473

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