What it does
数
Count to ten
Ichi to jū, the way it's called out on the floor during kihon.
令
Know the commands
Rei, yoi, hajime, yame — the words that run every class.
技
Name every move
Stance, strike, block and kick — with kanji, romaji and meaning.
Hear a command. Know it. Move.
A deck you can run through on the train, so the words have stopped being foreign by the time the sensei says them.