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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 864 · 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  2. 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  3. 3.A leapfrog list starts 1, 4 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 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  6. 6.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  7. 7.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  8. 8.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  9. 9.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  10. 10.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?
  11. 11.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  12. 12.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?
  13. 13.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?
  14. 14.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  15. 15.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  17. 17.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  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. 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  20. 20.A leapfrog list starts 8, 4 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.A leapfrog list starts 1, 9 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  27. 27.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?
  28. 28.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?
  29. 29.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  30. 30.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?
  31. 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  32. 32.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?
  33. 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  34. 34.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  35. 35.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  39. 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  40. 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =

Answer key

  1. 1089
  2. 473
  3. 407
  4. 759
  5. 726
  6. 1089
  7. 803
  8. 660
  9. 363
  10. 319
  11. 913
  12. 737
  13. 473
  14. 495
  15. 902
  16. 231
  17. 341
  18. 539
  19. 374
  20. 792
  21. 517
  22. 506
  23. 671
  24. 847
  25. 1034
  26. 924
  27. 759
  28. 550
  29. 253
  30. 528
  31. 902
  32. 198
  33. 418
  34. 1034
  35. 143
  36. 748
  37. 363
  38. 231
  39. 517
  40. 1056

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