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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 897 · 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. 1.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  2. 2.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?
  3. 3.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  4. 4.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?
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  7. 7.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  8. 8.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  9. 9.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  10. 10.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  11. 11.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  12. 12.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  20. 20.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  27. 27.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?
  28. 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  29. 29.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  30. 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  31. 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  33. 33.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  37. 37.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  38. 38.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?

Answer key

  1. 594
  2. 1001
  3. 583
  4. 451
  5. 682
  6. 869
  7. 198
  8. 429
  9. 781
  10. 979
  11. 1034
  12. 341
  13. 649
  14. 495
  15. 550
  16. 1287
  17. 957
  18. 198
  19. 957
  20. 847
  21. 671
  22. 539
  23. 935
  24. 660
  25. 726
  26. 616
  27. 231
  28. 1199
  29. 143
  30. 484
  31. 924
  32. 671
  33. 979
  34. 682
  35. 451
  36. 1034
  37. 704
  38. 572
  39. 1177
  40. 374

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