How can I practice math without doing homework?

In any other subject, the teacher teaches exactly how to do things and practice is considered an integral part of the class. But in math it is assumed that the teacher is lousy and the student is expected to learn the material by his own devices, and nobody cares where or how. The fact is you learn math better in wood shop than in a math class, because you get a ruler in your hand and actually do what you are learning. If teachers were actually teaching their courses, they would teach arithmetic in a wood shop and then have the students build geodesic domes in trigonometry class.

You don't say what level of math you are in, so there is no advice for you to practice. If you were to get interested in geodesic domes, you would spend the first few weeks doing homework to learn the skills. If you were to do woodworking to pick up some arithmetic skills, you would have to do some homework to develop what you learn. Physics and calculus are pretty much the same subject, but it takes five hours of homework every day for several weeks to learn how to do it.

I suggest you print this and show it to your teacher. The teacher is supposed GUIDE you to find some way to practice your lessons, not to challenge you to guide yourself. I could have been immensely more succcessful in high school if any of the teachers had bothered to connect my interest in electronics to something in the real world.