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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 876 · 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 6, 7 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  3. 3.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  4. 4.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  8. 8.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?
  9. 9.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  10. 10.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  11. 11.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?
  12. 12.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?
  13. 13.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  14. 14.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?
  15. 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  20. 20.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.A leapfrog list starts 4, 7 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  26. 26.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  27. 27.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  31. 31.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  32. 32.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  33. 33.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?
  34. 34.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  35. 35.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  39. 39.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?

Answer key

  1. 946
  2. 561
  3. 770
  4. 1023
  5. 1056
  6. 407
  7. 847
  8. 253
  9. 484
  10. 583
  11. 429
  12. 671
  13. 902
  14. 363
  15. 825
  16. 286
  17. 946
  18. 1089
  19. 319
  20. 781
  21. 847
  22. 880
  23. 198
  24. 836
  25. 693
  26. 715
  27. 462
  28. 319
  29. 594
  30. 638
  31. 979
  32. 594
  33. 198
  34. 495
  35. 902
  36. 418
  37. 616
  38. 506
  39. 880
  40. 726

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