A subring is a set of numbers that forms a ring when you use the same operations as the bigger ring.
Subrings are a mathematical idea and are used in algebra.
Examples:
The subring contains all the numbers that make a ring.
The subring has addition and multiplication, just like the big ring.
In math, a subring is a special kind of set of numbers.
The subring is like a little brother to the big ring.
The subring is like a small town inside the big city of the ring.
The subring is a ring inside a ring!