A proverb meaning it is pointless to regret things that are already done; equivalent to 'crying over spilt milk.'
試験に落ちて悔やんでも仕方がない。死んだ子の年を数えるようなものだ。
There's no point regretting failing the exam. It's like counting the age of a dead child (i.e., useless regret).
過去の失敗をいつまでも引きずるのは、死んだ子の年を数えるに等しい。
Dwelling on past failures forever is tantamount to pointless regret.
もう起こってしまったことを責めても意味がない。今できることを考えよう。死んだ子の年を数えるな。
Blaming the past that has already happened is pointless. Let's think about what we can do now. Don't cry over spilt milk.