my $M;
my $n;
my $remaining = $n % $M;
my $next_multiple = $n + $M - $remaining;

##</code><code>##

for my $n (1..20) {
  print "$n:\t";
  for my $M (2..5) {
    my $remaining = ($n-1) % $M;  # subtract one from the remainder
    my $next_multiple = $n-1  + $M - $remaining;
    print "$next_multiple\t";
  };
  print "\n";
};

##</code><code>##

perl -e "my $n=20; for(@ARGV){$x=$n-1+($_-($n-1)%$_);print qq($n\[$_] :$x\n)}" 2 3 4 5 6 7 8 9 10

# resp.

$x=$n-1+($M-($n-1)%$M)