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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 728 · 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 9, 2 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  3. 3.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?
  4. 4.A leapfrog list starts 7, 6 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  10. 10.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  11. 11.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  14. 14.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  15. 15.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?
  16. 16.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  21. 21.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  22. 22.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  23. 23.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  24. 24.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  25. 25.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  31. 31.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  32. 32.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  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, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  39. 39.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?
  40. 40.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =

Answer key

  1. 671
  2. 1056
  3. 1001
  4. 913
  5. 341
  6. 506
  7. 1023
  8. 770
  9. 473
  10. 1177
  11. 836
  12. 451
  13. 528
  14. 770
  15. 1199
  16. 759
  17. 803
  18. 902
  19. 704
  20. 374
  21. 759
  22. 506
  23. 957
  24. 253
  25. 913
  26. 319
  27. 1034
  28. 847
  29. 418
  30. 484
  31. 1056
  32. 308
  33. 1122
  34. 583
  35. 1144
  36. 660
  37. 891
  38. 231
  39. 814
  40. 286

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