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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 67 · 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. 1.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  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. 6.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  8. 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  9. 9.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  10. 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  11. 11.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  15. 15.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  20. 20.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?
  21. 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  22. 22.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  23. 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  24. 24.A leapfrog list starts 7, 3 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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 7, 9 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  28. 28.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  33. 33.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  34. 34.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  35. 35.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  36. 36.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  37. 37.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  38. 38.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?
  39. 39.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  40. 40.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?

Answer key

  1. 935
  2. 935
  3. 847
  4. 319
  5. 231
  6. 880
  7. 913
  8. 836
  9. 396
  10. 759
  11. 1144
  12. 473
  13. 814
  14. 495
  15. 671
  16. 451
  17. 847
  18. 308
  19. 418
  20. 341
  21. 550
  22. 429
  23. 143
  24. 649
  25. 1177
  26. 1177
  27. 1056
  28. 506
  29. 473
  30. 583
  31. 616
  32. 924
  33. 462
  34. 660
  35. 792
  36. 946
  37. 1012
  38. 946
  39. 770
  40. 198

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