已经有一段时间了，一直无法弄清楚如何对以下范围进行子网划分。有人可以帮我划分这些范围的子网并提供一些见解吗？
Subnet the 10.0.0.0/8 address space into 30 subnets.
Subnet the 172.16.0.0 address space into 13 subnets.
Subnet the 192.168.1.0/24 address space into 4 subnets.
Subnet the 192.168.0.0/24 address space into 7 subnets.