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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 434 · 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.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?
  2. 2.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  3. 3.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?
  4. 4.A leapfrog list starts 8, 5 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): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  6. 6.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  7. 7.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  8. 8.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?
  9. 9.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  12. 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  13. 13.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  16. 16.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  17. 17.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  18. 18.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  24. 24.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?
  25. 25.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  26. 26.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  28. 28.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  29. 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  30. 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  31. 31.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  32. 32.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  33. 33.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  38. 38.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  39. 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  40. 40.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =

Answer key

  1. 1001
  2. 429
  3. 462
  4. 880
  5. 660
  6. 550
  7. 979
  8. 605
  9. 671
  10. 803
  11. 231
  12. 935
  13. 583
  14. 858
  15. 968
  16. 737
  17. 198
  18. 946
  19. 363
  20. 253
  21. 704
  22. 803
  23. 572
  24. 847
  25. 374
  26. 1177
  27. 825
  28. 396
  29. 814
  30. 671
  31. 484
  32. 495
  33. 539
  34. 1111
  35. 902
  36. 825
  37. 803
  38. 583
  39. 759
  40. 561

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