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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 49 · 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. 1.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  2. 2.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?
  3. 3.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  4. 4.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  8. 8.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  9. 9.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  11. 11.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  12. 12.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?
  13. 13.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  15. 15.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?
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 2, 1 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): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  22. 22.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?
  23. 23.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?
  24. 24.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  26. 26.A leapfrog list starts 7, 5 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 3, 1 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, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  30. 30.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?
  31. 31.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  33. 33.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  34. 34.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  37. 37.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  38. 38.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  40. 40.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?

Answer key

  1. 715
  2. 231
  3. 638
  4. 495
  5. 407
  6. 814
  7. 913
  8. 726
  9. 462
  10. 946
  11. 396
  12. 462
  13. 1232
  14. 616
  15. 1056
  16. 572
  17. 792
  18. 924
  19. 605
  20. 198
  21. 1144
  22. 616
  23. 561
  24. 429
  25. 649
  26. 825
  27. 253
  28. 627
  29. 726
  30. 286
  31. 737
  32. 979
  33. 319
  34. 1001
  35. 693
  36. 1001
  37. 1199
  38. 1144
  39. 781
  40. 759

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