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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 777 · 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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  2. 2.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  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): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  5. 5.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  6. 6.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  7. 7.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  9. 9.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  11. 11.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  12. 12.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?
  13. 13.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  16. 16.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  17. 17.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  18. 18.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?
  19. 19.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  21. 21.A leapfrog list starts 6, 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): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  23. 23.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?
  24. 24.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  27. 27.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  29. 29.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?
  30. 30.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  31. 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  32. 32.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?
  33. 33.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  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 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  40. 40.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =

Answer key

  1. 484
  2. 1034
  3. 583
  4. 473
  5. 638
  6. 550
  7. 660
  8. 407
  9. 396
  10. 1023
  11. 902
  12. 572
  13. 1111
  14. 935
  15. 726
  16. 748
  17. 770
  18. 341
  19. 814
  20. 539
  21. 506
  22. 363
  23. 704
  24. 825
  25. 286
  26. 902
  27. 429
  28. 968
  29. 341
  30. 319
  31. 495
  32. 550
  33. 759
  34. 583
  35. 572
  36. 748
  37. 726
  38. 528
  39. 704
  40. 341

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