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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 65 · 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.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  4. 4.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  5. 5.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  6. 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  9. 9.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?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  12. 12.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?
  13. 13.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  15. 15.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  17. 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  18. 18.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?
  19. 19.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  21. 21.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  22. 22.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  24. 24.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?
  25. 25.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  26. 26.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  28. 28.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  34. 34.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1034
  2. 1122
  3. 781
  4. 913
  5. 506
  6. 1232
  7. 726
  8. 517
  9. 1034
  10. 979
  11. 407
  12. 869
  13. 957
  14. 803
  15. 1056
  16. 594
  17. 671
  18. 869
  19. 561
  20. 407
  21. 759
  22. 451
  23. 847
  24. 286
  25. 1034
  26. 561
  27. 759
  28. 484
  29. 308
  30. 319
  31. 594
  32. 660
  33. 1012
  34. 726
  35. 429
  36. 704
  37. 407
  38. 341
  39. 803
  40. 891

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