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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 590 · 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  5. 5.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.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?
  8. 8.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?
  9. 9.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  10. 10.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?
  11. 11.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  12. 12.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  13. 13.A leapfrog list starts 2, 6 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 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  19. 19.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?
  20. 20.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  21. 21.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  23. 23.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?
  24. 24.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  25. 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  26. 26.A leapfrog list starts 3, 4 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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  29. 29.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?
  30. 30.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  31. 31.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  32. 32.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  33. 33.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  34. 34.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  35. 35.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  38. 38.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  39. 39.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?
  40. 40.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =

Answer key

  1. 869
  2. 682
  3. 1056
  4. 1199
  5. 737
  6. 814
  7. 484
  8. 253
  9. 484
  10. 561
  11. 682
  12. 583
  13. 638
  14. 671
  15. 616
  16. 880
  17. 308
  18. 473
  19. 1089
  20. 847
  21. 1023
  22. 539
  23. 1122
  24. 1287
  25. 616
  26. 517
  27. 1287
  28. 1067
  29. 858
  30. 660
  31. 550
  32. 792
  33. 825
  34. 539
  35. 891
  36. 957
  37. 561
  38. 979
  39. 583
  40. 759

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