Question 312779
The square root can take on a positive or negative value,
{{{sqrt(64)=0 +- 8}}}
 {{{sqrt(16)=0 +- 4}}}
So the sum can also have multiple values. 
{{{sqrt(64)+sqrt(16)=8+4=12}}}
{{{sqrt(64)+sqrt(16)=8-4=4}}}
{{{sqrt(64)+sqrt(16)=-8+4=-4}}}
{{{sqrt(64)+sqrt(16)=-8-4=-12}}}