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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 928 · 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  5. 5.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?
  6. 6.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  7. 7.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 7, 3 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): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  10. 10.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  11. 11.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  13. 13.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  16. 16.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?
  17. 17.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  18. 18.A leapfrog list starts 2, 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): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  20. 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  21. 21.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  22. 22.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  23. 23.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?
  24. 24.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  28. 28.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?
  29. 29.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  30. 30.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  31. 31.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  36. 36.A leapfrog list starts 6, 5 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): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  38. 38.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?
  39. 39.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?
  40. 40.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 506
  2. 913
  3. 484
  4. 1034
  5. 308
  6. 341
  7. 880
  8. 649
  9. 473
  10. 198
  11. 836
  12. 319
  13. 1056
  14. 935
  15. 1001
  16. 341
  17. 1144
  18. 550
  19. 891
  20. 660
  21. 418
  22. 1001
  23. 517
  24. 473
  25. 935
  26. 429
  27. 792
  28. 847
  29. 407
  30. 957
  31. 363
  32. 847
  33. 671
  34. 627
  35. 1177
  36. 770
  37. 946
  38. 286
  39. 319
  40. 1023

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