Question

when we divide 2√3 by 2√3 it gives 3 how ?(2√3/2√3)

Answer 1

It doesn't.
$\frac{2\sqrt3}{2\sqrt3}=1$

Answer 2

Only if the individual doing the calculation makes a substantial mistake.

Any fraction with the same quantity in the numerator and denominator
always has the value of ' 1 ', (provided only that the quantity is not zero).