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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 984 · 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 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  2. 2.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?
  3. 3.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  4. 4.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?
  5. 5.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?
  6. 6.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  7. 7.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?
  8. 8.A leapfrog list starts 9, 9 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 1, 3 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): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  11. 11.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?
  12. 12.A leapfrog list starts 2, 5 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 7, 4 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 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  17. 17.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?
  18. 18.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?
  19. 19.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  20. 20.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?
  21. 21.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  22. 22.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  25. 25.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  27. 27.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  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.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?
  30. 30.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?
  31. 31.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  32. 32.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?
  33. 33.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?
  34. 34.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  35. 35.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  36. 36.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?
  37. 37.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  39. 39.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  40. 40.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 462
  2. 572
  3. 396
  4. 759
  5. 583
  6. 781
  7. 792
  8. 1287
  9. 319
  10. 495
  11. 198
  12. 550
  13. 737
  14. 902
  15. 847
  16. 847
  17. 616
  18. 1232
  19. 1122
  20. 561
  21. 286
  22. 770
  23. 1144
  24. 1111
  25. 814
  26. 517
  27. 1034
  28. 341
  29. 825
  30. 649
  31. 1144
  32. 528
  33. 1089
  34. 935
  35. 825
  36. 1232
  37. 748
  38. 759
  39. 528
  40. 308

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