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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 310 · 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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  2. 2.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  3. 3.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?
  4. 4.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  5. 5.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?
  6. 6.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  7. 7.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?
  8. 8.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  10. 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  11. 11.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?
  12. 12.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  19. 19.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  20. 20.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?
  21. 21.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  22. 22.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  25. 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  26. 26.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?
  27. 27.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 9, 9 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  32. 32.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  33. 33.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?
  34. 34.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?
  35. 35.A leapfrog list starts 2, 1 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 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  38. 38.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?
  39. 39.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  40. 40.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =

Answer key

  1. 1001
  2. 858
  3. 671
  4. 594
  5. 814
  6. 1111
  7. 935
  8. 253
  9. 792
  10. 759
  11. 968
  12. 583
  13. 231
  14. 1056
  15. 572
  16. 803
  17. 231
  18. 143
  19. 704
  20. 308
  21. 759
  22. 506
  23. 1012
  24. 616
  25. 396
  26. 946
  27. 737
  28. 451
  29. 1034
  30. 1287
  31. 638
  32. 418
  33. 1199
  34. 1023
  35. 198
  36. 605
  37. 550
  38. 506
  39. 825
  40. 913

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