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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 378 · 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 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  10. 10.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?
  11. 11.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  15. 15.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  16. 16.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?
  17. 17.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  18. 18.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  19. 19.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  20. 20.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?
  21. 21.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  27. 27.A leapfrog list starts 6, 7 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  30. 30.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  31. 31.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  32. 32.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  35. 35.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?
  36. 36.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?
  37. 37.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  38. 38.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?
  39. 39.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 792
  2. 539
  3. 495
  4. 407
  5. 319
  6. 715
  7. 550
  8. 803
  9. 253
  10. 968
  11. 396
  12. 253
  13. 704
  14. 968
  15. 682
  16. 847
  17. 726
  18. 770
  19. 847
  20. 836
  21. 792
  22. 363
  23. 429
  24. 803
  25. 902
  26. 616
  27. 946
  28. 693
  29. 550
  30. 495
  31. 759
  32. 759
  33. 1232
  34. 198
  35. 473
  36. 891
  37. 748
  38. 704
  39. 583
  40. 616

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