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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 204 · 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. 1.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  2. 2.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?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  5. 5.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  6. 6.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  7. 7.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?
  8. 8.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  9. 9.A leapfrog list starts 1, 1 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): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  11. 11.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  12. 12.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?
  13. 13.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?
  14. 14.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  15. 15.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  16. 16.A leapfrog list starts 8, 9 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 7, 2 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): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  19. 19.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  20. 20.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?
  21. 21.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  24. 24.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?
  25. 25.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  27. 27.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  28. 28.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?
  29. 29.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?

Answer key

  1. 792
  2. 561
  3. 506
  4. 1287
  5. 693
  6. 957
  7. 814
  8. 231
  9. 143
  10. 253
  11. 1056
  12. 374
  13. 847
  14. 693
  15. 286
  16. 1232
  17. 561
  18. 605
  19. 473
  20. 616
  21. 561
  22. 891
  23. 902
  24. 726
  25. 539
  26. 341
  27. 572
  28. 1122
  29. 759
  30. 594
  31. 913
  32. 363
  33. 715
  34. 880
  35. 605
  36. 759
  37. 407
  38. 396
  39. 462
  40. 737

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