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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 703 · 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.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?
  2. 2.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  4. 4.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?
  5. 5.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  6. 6.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  7. 7.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?
  8. 8.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?
  9. 9.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  10. 10.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  11. 11.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  13. 13.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  14. 14.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?
  15. 15.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?
  16. 16.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  19. 19.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?
  20. 20.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  23. 23.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  25. 25.A leapfrog list starts 4, 9 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 7, 2 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 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  31. 31.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  33. 33.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  34. 34.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  35. 35.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?
  36. 36.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  37. 37.A leapfrog list starts 6, 4 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): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 759
  2. 869
  3. 572
  4. 814
  5. 682
  6. 583
  7. 1001
  8. 1089
  9. 451
  10. 781
  11. 407
  12. 858
  13. 561
  14. 341
  15. 814
  16. 583
  17. 737
  18. 517
  19. 968
  20. 451
  21. 286
  22. 583
  23. 594
  24. 869
  25. 1012
  26. 561
  27. 374
  28. 1089
  29. 1287
  30. 671
  31. 473
  32. 495
  33. 341
  34. 418
  35. 759
  36. 902
  37. 682
  38. 616
  39. 748
  40. 902

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