Rubyで小数点桁数指定 ref: http://qiita.com/seteen/items/c8ac3a6349cd53ef25b7

file0.txt

test = 1.2345
puts sprintf("%.2f", test) # format("%.2f", test)も同様

file1.txt

1.2345.round    #=> 1
1.2345.round(2) #=> 1.23
1.2345.round(3) #=> 1.235 (四捨五入)
puts 1.2345.round(3) #=> 1.235