$4+3\cdot2+1\ =$  

 $4-3\cdot2-1\ =$  

 $1+2^2\ \cdot\ 3\ +4^2$  

 $1-2^2\ \cdot\ 3\ -4^2$  

 $\sqrt{25}-16$  

 $\sqrt{25}-\sqrt{16}\ =$  

 $25-\sqrt{16}\ =$  

 $\sqrt{25-16}=$  

 $\sqrt{25}\cdot16\ =$  

$\sqrt{25}\cdot16\ =$