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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 860 · 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. 2.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  3. 3.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?
  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): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  6. 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  7. 7.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  8. 8.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  9. 9.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  10. 10.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  12. 12.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?
  13. 13.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  14. 14.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?
  15. 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  16. 16.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  17. 17.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?
  18. 18.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  19. 19.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  21. 21.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  22. 22.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  23. 23.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?
  24. 24.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  25. 25.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?
  26. 26.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  27. 27.A leapfrog list starts 3, 2 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 8, 9 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): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  30. 30.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?
  31. 31.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?
  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. 33.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  34. 34.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?
  35. 35.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  37. 37.A leapfrog list starts 6, 1 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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  39. 39.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?

Answer key

  1. 803
  2. 319
  3. 737
  4. 1287
  5. 792
  6. 1232
  7. 869
  8. 495
  9. 451
  10. 594
  11. 1111
  12. 682
  13. 968
  14. 451
  15. 1111
  16. 418
  17. 616
  18. 1122
  19. 869
  20. 506
  21. 616
  22. 517
  23. 308
  24. 682
  25. 759
  26. 759
  27. 341
  28. 1232
  29. 1012
  30. 583
  31. 759
  32. 1232
  33. 1287
  34. 231
  35. 286
  36. 407
  37. 418
  38. 1177
  39. 759
  40. 1001

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