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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 421 · 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 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  3. 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  4. 4.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?
  5. 5.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  7. 7.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?
  8. 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  9. 9.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  10. 10.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  12. 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  13. 13.A leapfrog list starts 8, 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 7, 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 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  22. 22.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  24. 24.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  28. 28.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?
  29. 29.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  31. 31.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?
  32. 32.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  33. 33.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.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?
  40. 40.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =

Answer key

  1. 605
  2. 814
  3. 253
  4. 814
  5. 231
  6. 1232
  7. 341
  8. 759
  9. 880
  10. 869
  11. 319
  12. 308
  13. 792
  14. 1001
  15. 1199
  16. 748
  17. 836
  18. 429
  19. 473
  20. 693
  21. 693
  22. 704
  23. 847
  24. 495
  25. 726
  26. 1067
  27. 913
  28. 803
  29. 583
  30. 506
  31. 1232
  32. 1111
  33. 627
  34. 935
  35. 517
  36. 484
  37. 715
  38. 671
  39. 495
  40. 407

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