my %pres_answ = map {
    "s$_", {
        name => $presentations{"s$_"},
        grade => param("s$_");
    }
} 1..23;

{
    local ($\, $,) = ("\n", "\t");
    print @pres_answ{"s$_"}{qw/name grade/}
        for 1 .. 23;
}