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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 26 · 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  2. 2.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?
  3. 3.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. 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): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  8. 8.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?
  9. 9.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  10. 10.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  13. 13.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.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?
  17. 17.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  19. 19.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  20. 20.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?
  21. 21.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?
  22. 22.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  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. 24.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  25. 25.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  32. 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  35. 35.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  36. 36.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?
  37. 37.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?
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  40. 40.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?

Answer key

  1. 693
  2. 759
  3. 550
  4. 913
  5. 682
  6. 649
  7. 319
  8. 341
  9. 979
  10. 1177
  11. 869
  12. 1067
  13. 704
  14. 319
  15. 198
  16. 671
  17. 924
  18. 1023
  19. 143
  20. 363
  21. 847
  22. 396
  23. 935
  24. 693
  25. 858
  26. 1177
  27. 627
  28. 1034
  29. 583
  30. 715
  31. 902
  32. 583
  33. 286
  34. 583
  35. 572
  36. 671
  37. 638
  38. 869
  39. 737
  40. 847

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