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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 322 · 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, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  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.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?
  11. 11.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?
  12. 12.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  13. 13.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?
  14. 14.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  15. 15.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?
  16. 16.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  17. 17.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?
  18. 18.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  20. 20.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  21. 21.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?
  22. 22.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  23. 23.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?
  24. 24.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  25. 25.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  26. 26.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  27. 27.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  28. 28.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  30. 30.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  35. 35.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  37. 37.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  38. 38.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  40. 40.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =

Answer key

  1. 902
  2. 759
  3. 913
  4. 836
  5. 363
  6. 671
  7. 803
  8. 583
  9. 473
  10. 935
  11. 671
  12. 429
  13. 583
  14. 957
  15. 143
  16. 814
  17. 286
  18. 517
  19. 770
  20. 1232
  21. 231
  22. 550
  23. 891
  24. 594
  25. 671
  26. 616
  27. 748
  28. 671
  29. 1287
  30. 495
  31. 561
  32. 253
  33. 198
  34. 583
  35. 616
  36. 583
  37. 704
  38. 1144
  39. 1023
  40. 451

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