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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 94 · 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 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  2. 2.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?
  3. 3.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  11. 11.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?
  12. 12.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  14. 14.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?
  15. 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  28. 28.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  29. 29.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  30. 30.A leapfrog list starts 3, 9 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 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  33. 33.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 5, 5 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): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  38. 38.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?
  39. 39.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?
  40. 40.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1144
  2. 143
  3. 363
  4. 363
  5. 231
  6. 770
  7. 429
  8. 671
  9. 671
  10. 671
  11. 1089
  12. 847
  13. 649
  14. 143
  15. 418
  16. 506
  17. 550
  18. 770
  19. 286
  20. 759
  21. 418
  22. 1023
  23. 539
  24. 451
  25. 803
  26. 704
  27. 957
  28. 880
  29. 737
  30. 957
  31. 847
  32. 836
  33. 1122
  34. 319
  35. 451
  36. 715
  37. 231
  38. 759
  39. 561
  40. 924

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