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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 214 · 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. 1.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  2. 2.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?
  3. 3.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 3, 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 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  7. 7.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  12. 12.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?
  13. 13.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  15. 15.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  16. 16.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?
  17. 17.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?
  18. 18.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  19. 19.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  20. 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  21. 21.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  22. 22.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  24. 24.A leapfrog list starts 5, 1 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, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  28. 28.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?
  29. 29.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  30. 30.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?
  31. 31.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?
  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.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?
  34. 34.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  35. 35.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  36. 36.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  37. 37.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?
  38. 38.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?
  39. 39.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  40. 40.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?

Answer key

  1. 286
  2. 693
  3. 605
  4. 429
  5. 869
  6. 231
  7. 1034
  8. 473
  9. 979
  10. 451
  11. 319
  12. 748
  13. 715
  14. 682
  15. 979
  16. 858
  17. 1287
  18. 418
  19. 253
  20. 660
  21. 836
  22. 1012
  23. 198
  24. 363
  25. 781
  26. 957
  27. 583
  28. 286
  29. 671
  30. 847
  31. 374
  32. 704
  33. 1199
  34. 1144
  35. 451
  36. 759
  37. 319
  38. 1232
  39. 913
  40. 583

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