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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 656 · 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.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?
  2. 2.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?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  5. 5.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?
  6. 6.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  7. 7.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  8. 8.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  9. 9.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 9, 1 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  15. 15.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?
  16. 16.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  17. 17.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?
  18. 18.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  19. 19.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  20. 20.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  26. 26.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  30. 30.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  31. 31.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  32. 32.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?
  33. 33.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  34. 34.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  37. 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  38. 38.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  40. 40.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =

Answer key

  1. 418
  2. 198
  3. 451
  4. 462
  5. 924
  6. 759
  7. 660
  8. 649
  9. 627
  10. 253
  11. 671
  12. 583
  13. 396
  14. 308
  15. 803
  16. 935
  17. 759
  18. 429
  19. 253
  20. 374
  21. 484
  22. 1111
  23. 231
  24. 979
  25. 1287
  26. 451
  27. 858
  28. 1232
  29. 594
  30. 286
  31. 1287
  32. 704
  33. 198
  34. 946
  35. 671
  36. 880
  37. 902
  38. 682
  39. 770
  40. 1144

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