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diff --git a/challenge-120/paul-fajman/perl/ch-1.pl b/challenge-120/paul-fajman/perl/ch-1.pl
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+#!/usr/bin/perl
+
+# Weekly Challenge 120 Task #1
+# You are given a positive integer $N less than or equal to 255.
+# Write a script to swap the odd positioned bit with even positioned 
+# bit and print the decimal equivalent of the new binary representation.
+
+use strict;
+use warnings;
+
+my $number = $ARGV[0];
+my $binary = sprintf ('%b', $number);
+my ($out1, $out2);
+my $final;
+
+# Determine if we have odd or even amount of binary digits
+if (length($binary) % 2) {
+  $binary = "0".$binary # Odd so add leading 0.
+}
+
+my @binary = split(//,$binary);
+my $i;
+my $new;
+
+# Loop over the binary number to perform swap
+for ($i=0; $i<$#binary+1; $i+=2) {
+  $out1.= $binary[$i].$binary[$i+1]." ";
+  $out2.= $binary[$i+1].$binary[$i]." ";
+  $new.="$binary[$i+1]"."$binary[$i]";
+}
+
+$final = eval("0b".$new); # Convert back to decimal number
+chomp($out1);
+chomp($out2);
+
+print "Input: \$N = $number\n";
+print "Output: $final\n\n";
+
+print "Binary representation of the given number is $out1\n";
+print "The new binary representation after the odd/even swap is $out2\n";
+print "The decimal equivalent of $new is $final\n";
+