$text =~ /\b(\d+)/

##</code><code>##

if ($text =~ /\b(\d+)\b/) {
   print("Matched $1\n");
}

##</code><code>##

# The first standalone number.
$text =~ /\b(\d+)\b/

##</code><code>##

# By context.
$text =~ /(\d+) months? old/

##</code><code>##

# The last number.
$text =~ /^.*\b(\d+)/