As I understand it, unary plus predecedence here needs to be defined with parentheses; hence to get 21 using the correct precedence: 
#!/usr/bin/perl -l

use strict;
use warnings; 
  
print my $q = 1;
print $q + +(4*5);
print $q+4*5;
print $q+ 4*5;

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In reply to Re: Operator precedence of unary plus (Bug or Feature) by Khen1950fx
in thread Operator precedence of unary plus (Bug or Feature) by LanX

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