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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 514 · 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  2. 2.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  8. 8.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  13. 13.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?
  14. 14.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  16. 16.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  17. 17.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  18. 18.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?
  19. 19.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  24. 24.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?
  25. 25.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?
  26. 26.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  27. 27.A leapfrog list starts 9, 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 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  29. 29.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?
  30. 30.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?
  31. 31.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  34. 34.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  36. 36.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?
  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. 38.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  39. 39.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  40. 40.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?

Answer key

  1. 638
  2. 902
  3. 902
  4. 198
  5. 1089
  6. 759
  7. 847
  8. 308
  9. 286
  10. 506
  11. 1199
  12. 671
  13. 374
  14. 968
  15. 638
  16. 495
  17. 605
  18. 649
  19. 726
  20. 979
  21. 341
  22. 1144
  23. 451
  24. 495
  25. 253
  26. 814
  27. 671
  28. 671
  29. 1122
  30. 1001
  31. 649
  32. 814
  33. 1089
  34. 913
  35. 770
  36. 231
  37. 418
  38. 1199
  39. 1122
  40. 1177

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