Read the following text carefully!

    My name is Ardian. I am a seventh grade student. I study at SMP Jaya. I always go to school every Monday to Friday. Besides studying at school, I have lots of activities to do every day.

    I always joins a Mathematics course on Mondays. After having the Mathematics, I still have an English course. I practise playing basketball with my team at school every Tuesday. I practise basketball only once a week. I have Mathematics and Physics course on Wednesdays. I also join a guitar course every Thursday. I like playing a guitar. That's why I join the course. I must join the Scouts at school every Friday. Saturday is my favourite day for I can read a comic strip after school. My parents sometimes take me to go out for dinner or to watch a film in a cinema. My parents and I usually visit my grandparents on Sundays.

Answer the questions according to the text!

When does he join the Mathematics course?