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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 19 · 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 1, 4 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  3. 3.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  6. 6.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  7. 7.A leapfrog list starts 7, 1 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  9. 9.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  10. 10.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  11. 11.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  13. 13.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  14. 14.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?
  15. 15.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  16. 16.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  18. 18.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  20. 20.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  21. 21.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.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?
  24. 24.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  25. 25.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  30. 30.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  31. 31.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?
  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.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?
  34. 34.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  38. 38.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?
  39. 39.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?
  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. 407
  2. 506
  3. 319
  4. 847
  5. 1023
  6. 143
  7. 473
  8. 308
  9. 517
  10. 671
  11. 880
  12. 814
  13. 924
  14. 825
  15. 847
  16. 671
  17. 825
  18. 660
  19. 946
  20. 374
  21. 1199
  22. 1056
  23. 693
  24. 979
  25. 231
  26. 341
  27. 638
  28. 891
  29. 1232
  30. 1144
  31. 792
  32. 880
  33. 550
  34. 1111
  35. 704
  36. 484
  37. 429
  38. 759
  39. 616
  40. 253

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