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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 20 · 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, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  4. 4.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  11. 11.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  16. 16.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  17. 17.A leapfrog list starts 4, 5 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 5, 2 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, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  20. 20.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?
  21. 21.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  29. 29.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  30. 30.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  31. 31.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?
  32. 32.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  33. 33.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  35. 35.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  36. 36.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?
  37. 37.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  39. 39.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  40. 40.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =

Answer key

  1. 231
  2. 715
  3. 1023
  4. 1056
  5. 726
  6. 286
  7. 880
  8. 616
  9. 484
  10. 770
  11. 1023
  12. 319
  13. 847
  14. 726
  15. 429
  16. 594
  17. 660
  18. 451
  19. 561
  20. 814
  21. 473
  22. 781
  23. 198
  24. 1177
  25. 803
  26. 649
  27. 968
  28. 528
  29. 1122
  30. 319
  31. 902
  32. 814
  33. 847
  34. 341
  35. 847
  36. 374
  37. 792
  38. 451
  39. 759
  40. 1232

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