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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 863 · 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 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  3. 3.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  4. 4.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  9. 9.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  14. 14.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?
  15. 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  16. 16.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?
  17. 17.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?
  18. 18.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  23. 23.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  24. 24.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  25. 25.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?
  26. 26.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  29. 29.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  33. 33.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  34. 34.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  37. 37.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  38. 38.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  39. 39.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  40. 40.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?

Answer key

  1. 803
  2. 902
  3. 891
  4. 1122
  5. 462
  6. 319
  7. 374
  8. 429
  9. 957
  10. 847
  11. 143
  12. 913
  13. 1177
  14. 693
  15. 418
  16. 1287
  17. 902
  18. 924
  19. 935
  20. 847
  21. 693
  22. 935
  23. 528
  24. 231
  25. 616
  26. 1023
  27. 1144
  28. 682
  29. 781
  30. 638
  31. 759
  32. 759
  33. 451
  34. 935
  35. 253
  36. 198
  37. 1199
  38. 594
  39. 495
  40. 836

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