Learning maths in school is all about developing the skills you already know. As you advance through the years you learn some new techniques and start doing more advanced maths using the new things you keep on learning but also using math skills you have been learning since a young age. The only problem with this is that as a kid it can be very easy to get distracted in lessons and fall behind on some subjects. If you don't catch up then it becomes even harder to understand new, more complex levels of maths. I want to help your child solve his or her doubts and understand sub-topics which they find harder so they can be completely up to date with the rest of their class mates. Being a kid I completely understand that sitting at a desk and learning about something that you might not find so interesting can be really boring and make you lose interest so I suggest the 30 minute classes so that your child can stay focused and enjoy the class.