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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 139 · 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, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 8, 2 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): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  7. 7.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?
  8. 8.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  9. 9.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 6, 6 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 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  17. 17.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  23. 23.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?
  24. 24.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  25. 25.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?
  26. 26.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?
  27. 27.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  30. 30.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  32. 32.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  34. 34.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  35. 35.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?
  36. 36.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  37. 37.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  39. 39.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?
  40. 40.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =

Answer key

  1. 1122
  2. 847
  3. 902
  4. 616
  5. 572
  6. 902
  7. 1144
  8. 198
  9. 418
  10. 935
  11. 550
  12. 858
  13. 341
  14. 572
  15. 1034
  16. 1144
  17. 286
  18. 1023
  19. 649
  20. 429
  21. 616
  22. 319
  23. 770
  24. 715
  25. 605
  26. 1034
  27. 429
  28. 693
  29. 1056
  30. 847
  31. 979
  32. 935
  33. 484
  34. 1287
  35. 1089
  36. 506
  37. 1001
  38. 561
  39. 319
  40. 935

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