When we use "round(perc,2)" in the final line, what does the argument '2' do?

Answer 1

It determines to which digit from decimal point the number will be rounded up to.

round(23.3467, 1) will be 23.3
round(23.3467, 2) will be 23.35
round(23.3467, 3) will be 23.347

Answer 2

argument here serve as the number of digits UpTo which it would be round off
example (28.4567 , 3) will be 28.456
and so on ...