Split the class into groups. For a class of 30-ish, I recommend 6 groups.
Explain the rules and the grid and have students repeat the topic and numbers so they know how to ask for a question (for example, "Japanese to English 400").
Have each group choose a question and answer them in order. If they get it wrong, open it up to any group to answer. If a group is wrong, deduct points, if they are right add points.
After each group has gone once, open questions up so that although groups still pick questions in order, there is no longer chooser priority. This way, once the teacher/ALT finishes reading the question, any student can answer and win (or lose) points for any group. Be strict in that they not raise their hands/hit their desks/buzzers until after the teacher finishes reading the question.
Feel free to change the teacher in Unit 5, 200 to you or your JTE.