How to efficiently subnet a network

Question

I have base ip address 10.6.0.0/16. I need to divide this network into 12 subnets, and I need at least 80 computers in one network. Please explain how to calculate correctly subnets. I understand that subnets count should be power of two, so the nearest is 16. But I don't understand what should I do next. Please explain. Thanks.

Answer 1

Like this:

10.6.0.0/24
10.6.1.0/24
10.6.2.0/24
10.6.3.0/24
10.6.4.0/24
10.6.5.0/24
10.6.6.0/24
10.6.7.0/24
10.6.8.0/24
10.6.9.0/24
10.6.10.0/24
10.6.11.0/24
10.6.12.0/24
...
10.6.254.0/24

each /24 can hold 250+ hosts plus gateway address and broadcast address.