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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 763 · 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  5. 5.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  6. 6.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 5, 6 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, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  11. 11.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  12. 12.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  13. 13.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?
  14. 14.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  16. 16.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  17. 17.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  18. 18.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?
  19. 19.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  20. 20.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?
  21. 21.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  22. 22.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  23. 23.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  24. 24.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?
  25. 25.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?
  26. 26.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  27. 27.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  28. 28.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  30. 30.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  31. 31.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  32. 32.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  35. 35.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  36. 36.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  39. 39.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  40. 40.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?

Answer key

  1. 308
  2. 473
  3. 825
  4. 979
  5. 1056
  6. 924
  7. 517
  8. 363
  9. 803
  10. 539
  11. 737
  12. 231
  13. 803
  14. 1067
  15. 253
  16. 902
  17. 759
  18. 374
  19. 198
  20. 583
  21. 506
  22. 418
  23. 319
  24. 847
  25. 198
  26. 1089
  27. 660
  28. 935
  29. 1067
  30. 891
  31. 550
  32. 506
  33. 1001
  34. 473
  35. 1111
  36. 363
  37. 979
  38. 627
  39. 957
  40. 649

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