It is important (and surprisingly difficult) to specify sufficiently complete requirements. In your first example, I can think of several "corner cases" where the desired output is not specified.

Input is not an integer

Input is not an odd integer

Input is less than '1'

Output is to long to print on one line

Etc. - I doubt that I thought of all of them

I assume that you mean "Compute the sum of the odd integers less than 'n' when 'n' is in the range 1 through 50. Display the result as shown."

It may be beyond the scope of your current assignment, but it is worth noting that CPAN modules can be helpful even in small programs.

use strict;
use warnings;
use integer;
use IO::Prompt::Hooked;
use List::Util qw(sum0);

my $max = prompt("Enter Limiting number (1-50)");
my @terms = grep { $_ % 2 } 1 .. $max;
my $sum = sum0 @terms;
my $expression = join '+', @terms;
print "($expression)=$sum\n";
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