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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 306 · 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 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  5. 5.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  6. 6.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  8. 8.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  9. 9.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  10. 10.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  15. 15.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  16. 16.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?
  17. 17.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?
  18. 18.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  19. 19.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  22. 22.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?
  23. 23.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  24. 24.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?
  25. 25.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?
  26. 26.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  27. 27.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.A leapfrog list starts 2, 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 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  38. 38.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?

Answer key

  1. 363
  2. 605
  3. 869
  4. 693
  5. 660
  6. 341
  7. 341
  8. 319
  9. 1089
  10. 561
  11. 979
  12. 319
  13. 1144
  14. 308
  15. 495
  16. 253
  17. 550
  18. 473
  19. 286
  20. 561
  21. 660
  22. 616
  23. 704
  24. 1232
  25. 451
  26. 968
  27. 143
  28. 814
  29. 341
  30. 781
  31. 462
  32. 968
  33. 1089
  34. 660
  35. 902
  36. 1023
  37. 924
  38. 1034
  39. 1122
  40. 1034

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