my %nums = (
  four  => 4,
  one   => 1,
  three => 3,
  two   => 2,
);

for %nums.keys.sort: { %nums{$^a} <=> %nums{$^b} } -> $key {
    say "$key {%nums{$key}}";
}

##</code><code>##

one 1
two 2
three 3
four 4