#### Answer

The simplified form of $\frac{10-20\sqrt 3}{2} $ is $5-10\sqrt 3$.

#### Work Step by Step

$\frac{10-20\sqrt 3}{2} $
Step 1: A common factor of 10 and 20 is 2. Hence, 10 and 20 can be divided by 2 and 2 can be taken outside the bracket:
$\frac{2(5-10\sqrt 3)}{2} $.
Step 2: 2 can be cancelled from both numerator and denominator and we will be left with
$5-10\sqrt 3$.