Since noone has linked to it yet: What Every Programmer Should Know About Floating-Point Arithmetic

Note that if you don't care about taking a performance hit (which can be quite significant depending on how many variables and calculations you're using in your actual script, so make sure to benchmark), you can enable bignum. Note that it can also be enabled only for smaller lexical scopes, which is what I'm showing here:

my $x1 = (1.15*170)+0.50;
my $x2 = int($x1);
print "A: Number is: $x1, Integer part is: $x2\n";
{
    use bignum;
    my $x3 = (1.15*170)+0.50;
    my $x4 = int($x3);
    print "B: Number is: $x3, Integer part is: $x4\n";
}
__END__

A: Number is: 196, Integer part is: 195
B: Number is: 196, Integer part is: 196
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