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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 968 · 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 4, 1 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  3. 3.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  4. 4.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  5. 5.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  6. 6.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  7. 7.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.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?
  10. 10.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  11. 11.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  13. 13.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  23. 23.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  24. 24.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  28. 28.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  32. 32.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?
  33. 33.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  35. 35.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?
  36. 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  37. 37.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  38. 38.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?
  39. 39.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  40. 40.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?

Answer key

  1. 308
  2. 594
  3. 1001
  4. 495
  5. 814
  6. 1177
  7. 693
  8. 891
  9. 198
  10. 143
  11. 484
  12. 1232
  13. 836
  14. 1001
  15. 847
  16. 231
  17. 616
  18. 924
  19. 748
  20. 1089
  21. 913
  22. 979
  23. 946
  24. 1012
  25. 528
  26. 869
  27. 407
  28. 759
  29. 660
  30. 286
  31. 253
  32. 517
  33. 902
  34. 1012
  35. 759
  36. 308
  37. 363
  38. 737
  39. 869
  40. 627

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