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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 177 · 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 3, 3 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): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  3. 3.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?
  4. 4.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  5. 5.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  6. 6.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  12. 12.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  18. 18.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?
  19. 19.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  20. 20.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  21. 21.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  22. 22.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  25. 25.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  26. 26.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  27. 27.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  28. 28.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  29. 29.A leapfrog list starts 8, 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): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  36. 36.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  37. 37.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?
  38. 38.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 429
  2. 814
  3. 198
  4. 671
  5. 660
  6. 759
  7. 671
  8. 825
  9. 968
  10. 143
  11. 418
  12. 979
  13. 1001
  14. 858
  15. 231
  16. 737
  17. 770
  18. 319
  19. 869
  20. 1111
  21. 539
  22. 308
  23. 748
  24. 759
  25. 517
  26. 1023
  27. 836
  28. 1144
  29. 704
  30. 407
  31. 792
  32. 1287
  33. 759
  34. 407
  35. 836
  36. 594
  37. 1144
  38. 737
  39. 583
  40. 286

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