A larger network can be split by borrowing host bits. The subnet table renders every resulting row and recomputes each range from the prefixes.
highlighted = computed this step
Why splitting borrows bits
Subnetting turns host bits into more network bits. The table shows every resulting range instead of asking the reader to trust a count.
/24
Borrowed bits make rows
Changing /24 to /26 borrows 2 bits. That makes 4 subnets.
2⇒4
Read the split
The third row is 192.168.1.128/26, and the fourth row starts at 192.168.1.192. Each row has 62 usable hosts.
subnets=4
Summary
Borrowed bits multiply subnet rows, and each row's host range is recomputed from its network and mask. Address arithmetic only; timing/throughput is not modeled here.