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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 999 · 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. 1.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  6. 6.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  9. 9.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  10. 10.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?
  11. 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  12. 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  16. 16.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?
  17. 17.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  22. 22.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?
  23. 23.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?
  24. 24.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  25. 25.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  27. 27.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  28. 28.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  29. 29.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  32. 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  33. 33.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?
  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.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?
  36. 36.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?
  37. 37.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?
  38. 38.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  39. 39.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?
  40. 40.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =

Answer key

  1. 924
  2. 451
  3. 1067
  4. 935
  5. 451
  6. 495
  7. 429
  8. 495
  9. 286
  10. 825
  11. 748
  12. 363
  13. 1287
  14. 341
  15. 396
  16. 627
  17. 1012
  18. 825
  19. 605
  20. 869
  21. 1023
  22. 858
  23. 671
  24. 913
  25. 594
  26. 143
  27. 572
  28. 1287
  29. 605
  30. 286
  31. 429
  32. 231
  33. 341
  34. 583
  35. 704
  36. 968
  37. 759
  38. 407
  39. 671
  40. 1232

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