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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 627 · 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, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  2. 2.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?
  3. 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  4. 4.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?
  5. 5.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?
  6. 6.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  8. 8.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 3, 1 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, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  11. 11.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  12. 12.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  13. 13.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  14. 14.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?
  15. 15.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  16. 16.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?
  17. 17.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  23. 23.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  24. 24.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  25. 25.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  26. 26.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?
  27. 27.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  30. 30.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  31. 31.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  32. 32.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  33. 33.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?
  34. 34.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  37. 37.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?
  38. 38.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  39. 39.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?
  40. 40.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =

Answer key

  1. 682
  2. 528
  3. 506
  4. 847
  5. 407
  6. 341
  7. 1232
  8. 935
  9. 253
  10. 803
  11. 946
  12. 462
  13. 198
  14. 561
  15. 770
  16. 715
  17. 253
  18. 1177
  19. 198
  20. 1111
  21. 737
  22. 1034
  23. 704
  24. 429
  25. 495
  26. 451
  27. 231
  28. 341
  29. 1122
  30. 1111
  31. 1012
  32. 374
  33. 968
  34. 660
  35. 814
  36. 572
  37. 396
  38. 616
  39. 825
  40. 396

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