Always use spaces around operators, after commas, colons and semicolons, around { and before }. White space might be (mostly) irrelevant to the Ruby interpreter, but its proper use is the key to writing easily readable code. Also it makes the design more readable and code much cleaner. product = 1 * 2 array = [ 1 , 2 , 3 , 4 , 5 ] array.map { |a| a + 2 } There should be no spaces after (, [ or before ], ) these brackets. [ 'ankur' , 'vyas' ] sum(a, b) Also don't use spaces in while providing the range. Use 5 .. 9 over 5 .. 9 Use 'a' .. 'z' over 'a' .. 'z' When using switch case statements use the following indentation. case when input = '+' puts 'The operation is addition' when '-' puts 'The operation is subtraction' when '*' puts 'The operation is multiplication' else puts 'The operat...