Here is an example of a response letter:
From: Friend@mail.ru
To: Zoe@friend.uk
Subject: Homework
Hi Zoe,
Thanks for your email! It's cool that your teachers don't give you much homework. I usually do my homework in the afternoon, after school. My teachers give me quite a lot of homework, especially on weekends. I think the most difficult subject for me is Maths, because I sometimes struggle with the formulas.
How about you? What do you usually do in your free time?
Write back soon!
Best,
[Your Name]