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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 450 · 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  2. 2.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  3. 3.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  6. 6.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?
  7. 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  12. 12.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  13. 13.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?
  14. 14.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  15. 15.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  21. 21.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?
  22. 22.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  23. 23.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  24. 24.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  26. 26.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?
  27. 27.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  28. 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  29. 29.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?
  30. 30.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?
  31. 31.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =

Answer key

  1. 550
  2. 781
  3. 880
  4. 847
  5. 308
  6. 594
  7. 1111
  8. 924
  9. 715
  10. 869
  11. 627
  12. 198
  13. 308
  14. 979
  15. 946
  16. 231
  17. 660
  18. 627
  19. 1111
  20. 1199
  21. 968
  22. 858
  23. 1056
  24. 583
  25. 396
  26. 913
  27. 660
  28. 671
  29. 946
  30. 1001
  31. 737
  32. 957
  33. 869
  34. 396
  35. 1122
  36. 649
  37. 715
  38. 814
  39. 363
  40. 715

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