Explain surd to me as mathematics topic?

Answer 1

Surds are based on roots.

Root 8 can be split into root 4 and root 2; as there's a root to 4, get that number, and multiply it by the remaining root.

So root 8 = 2 root 2.

Root 40 would be 2 root 10

Root 48 would be root 4, root 4, root 3

Root 48 = 4 root 3.