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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 124 · 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. 1.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  2. 2.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?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  5. 5.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  6. 6.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  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. 8.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  9. 9.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.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?
  12. 12.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  15. 15.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?
  16. 16.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  21. 21.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?
  22. 22.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  23. 23.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?
  24. 24.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  25. 25.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  29. 29.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  30. 30.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  31. 31.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?
  32. 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  33. 33.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  34. 34.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  36. 36.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  37. 37.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  40. 40.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =

Answer key

  1. 748
  2. 616
  3. 407
  4. 1034
  5. 1199
  6. 825
  7. 528
  8. 913
  9. 880
  10. 341
  11. 847
  12. 1056
  13. 671
  14. 715
  15. 649
  16. 693
  17. 374
  18. 198
  19. 825
  20. 286
  21. 671
  22. 660
  23. 671
  24. 539
  25. 517
  26. 583
  27. 759
  28. 880
  29. 869
  30. 396
  31. 253
  32. 561
  33. 726
  34. 770
  35. 737
  36. 902
  37. 462
  38. 528
  39. 869
  40. 759

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