#!/usr/bin/perl 

$nbArguments = $#ARGV + 1; 
print "number of arguments: $nbArgumentsn"; 
exit(1) unless $nbArguments == 3; 
$a = $ARGV[0]; 
$b = $ARGV[2]; 
$operation = $ARGV[1]; 

if ($operation eq "+") 
{$result = $a + $b; 

}elsif ($operation eq "-") 
{$result = $a - $b; 

}elsif ($operation eq "/") 
{$result = $a / $b; 

}elsif ($operation eq "x") 
{$result = $a * $b; 

}print "$a 
$operation $b = $result \n"; 

--------------------------------------- 

This is what I tried and failed! 

#!/usr/bin/perl 

$nbArguments = $#ARGV + 1; 
print "number of arguments: $nbArgumentsn"; 
exit(1) unless $nbArguments == 5; 
$a = $ARGV[0]; 
$operation = $ARGV[1]; 
$b = $ARGV[2]; 
$c = $ARGV[3]; 

if ($operation eq "+") 
{$result = $a + $b + $c; 

}elsif ($operation eq "-") 
{$result = $a - $b; 

}elsif ($operation eq "/") 
{$result = $a / $b; 

}elsif ($operation eq "x") 
{$result = $a * $b; 

}print "$a 
$operation $b 
$operation $c 
= $result \n";