Math error in Perl

[Mark Berryman]

Could someone please explain to me why only the last two expressions
return correct results?

$ perl -e "print (212-32)*5/9;"
180
$ perl -e "print (212-32)*5;"
180
$ perl -e "print (212-32);"
180
$ perl -e "print 5*(212-32)/9;"
100

Mark Berryman