### 4.5.1 
[good guess](good-guess/my_solution.rb)
### 4.5.2 
[calc letter grade](calculate-grade/my_solution.rb)
### 4.5.3 
[triangle sides](triangle-side/my_solution.rb)
### 4.5.4 
[detecting leap years](leap-year/my_solution.rb)
### 4.5.5 
[detecting simple substrings](11-simple-substrings/my_solution.rb)
Add MD file organizing section
Add MD file organizing section
