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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 376 · 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 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  4. 4.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?
  5. 5.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  12. 12.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  14. 14.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  18. 18.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  19. 19.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  22. 22.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  23. 23.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?
  24. 24.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?
  25. 25.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  28. 28.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?
  29. 29.A leapfrog list starts 1, 6 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): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  34. 34.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?
  35. 35.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  36. 36.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  37. 37.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?
  38. 38.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?
  39. 39.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  40. 40.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?

Answer key

  1. 1111
  2. 594
  3. 858
  4. 638
  5. 583
  6. 715
  7. 550
  8. 847
  9. 561
  10. 704
  11. 308
  12. 143
  13. 946
  14. 803
  15. 1287
  16. 341
  17. 627
  18. 462
  19. 528
  20. 814
  21. 1067
  22. 671
  23. 759
  24. 484
  25. 473
  26. 649
  27. 594
  28. 429
  29. 583
  30. 935
  31. 737
  32. 1232
  33. 1144
  34. 759
  35. 737
  36. 539
  37. 803
  38. 759
  39. 935
  40. 1199

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