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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 874 · 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. 1.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  2. 2.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?
  3. 3.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?
  4. 4.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  5. 5.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?
  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.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?
  8. 8.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  10. 10.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?
  11. 11.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  12. 12.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  13. 13.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?
  14. 14.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  15. 15.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  18. 18.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  21. 21.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  22. 22.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  23. 23.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  25. 25.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?
  26. 26.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  32. 32.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  33. 33.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?
  34. 34.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  35. 35.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  36. 36.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  40. 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =

Answer key

  1. 1056
  2. 198
  3. 671
  4. 781
  5. 693
  6. 143
  7. 583
  8. 286
  9. 605
  10. 1089
  11. 726
  12. 880
  13. 737
  14. 616
  15. 594
  16. 396
  17. 671
  18. 539
  19. 484
  20. 1199
  21. 748
  22. 957
  23. 396
  24. 143
  25. 638
  26. 781
  27. 451
  28. 1067
  29. 759
  30. 517
  31. 451
  32. 1012
  33. 319
  34. 759
  35. 506
  36. 517
  37. 539
  38. 726
  39. 638
  40. 847

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