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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 655 · 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 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  4. 4.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?
  5. 5.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  6. 6.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  7. 7.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?
  8. 8.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  9. 9.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?
  10. 10.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  13. 13.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  15. 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  16. 16.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  17. 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  18. 18.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  19. 19.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?
  20. 20.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  21. 21.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?
  22. 22.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  24. 24.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  25. 25.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  26. 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  27. 27.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 286
  2. 198
  3. 1089
  4. 198
  5. 671
  6. 770
  7. 913
  8. 374
  9. 407
  10. 539
  11. 594
  12. 363
  13. 143
  14. 1177
  15. 825
  16. 1001
  17. 814
  18. 737
  19. 1012
  20. 1144
  21. 660
  22. 715
  23. 671
  24. 572
  25. 198
  26. 583
  27. 748
  28. 561
  29. 814
  30. 979
  31. 319
  32. 869
  33. 462
  34. 319
  35. 638
  36. 759
  37. 583
  38. 572
  39. 781
  40. 704

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