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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 823 · 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. 1.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 8, 6 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 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  10. 10.A leapfrog list starts 4, 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.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?
  13. 13.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?
  14. 14.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?
  15. 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  16. 16.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  18. 18.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  19. 19.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  22. 22.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  23. 23.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  24. 24.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  25. 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  26. 26.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  28. 28.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  29. 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  35. 35.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  36. 36.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?
  37. 37.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?

Answer key

  1. 1067
  2. 1089
  3. 550
  4. 407
  5. 946
  6. 1056
  7. 968
  8. 484
  9. 198
  10. 396
  11. 253
  12. 341
  13. 836
  14. 704
  15. 781
  16. 880
  17. 1089
  18. 495
  19. 858
  20. 561
  21. 924
  22. 1056
  23. 374
  24. 1089
  25. 726
  26. 572
  27. 1232
  28. 561
  29. 363
  30. 814
  31. 143
  32. 495
  33. 847
  34. 792
  35. 1111
  36. 847
  37. 605
  38. 1111
  39. 682
  40. 770

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