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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 713 · 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. 1.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  2. 2.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  3. 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  4. 4.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?
  5. 5.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  10. 10.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?
  11. 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  12. 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  13. 13.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?
  14. 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  15. 15.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  21. 21.A leapfrog list starts 2, 3 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  29. 29.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  30. 30.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?
  31. 31.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  32. 32.A leapfrog list starts 7, 2 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. 34.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  35. 35.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  36. 36.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?
  37. 37.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  39. 39.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?
  40. 40.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =

Answer key

  1. 407
  2. 924
  3. 286
  4. 583
  5. 748
  6. 396
  7. 528
  8. 605
  9. 748
  10. 286
  11. 253
  12. 484
  13. 880
  14. 627
  15. 627
  16. 649
  17. 253
  18. 374
  19. 1287
  20. 198
  21. 374
  22. 902
  23. 473
  24. 1199
  25. 1111
  26. 583
  27. 253
  28. 319
  29. 979
  30. 341
  31. 737
  32. 561
  33. 759
  34. 1111
  35. 682
  36. 231
  37. 858
  38. 671
  39. 407
  40. 935

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