$3\ +\ 1\ =$  

(a)  

 $6\ +\ 4\ =$  

(a)  

 $7\ +\ 7\ =$  

(a)  

 $9\ +\ 2\ =$  

(a)  

 $10\ +\ 10\ =$  

(a)  

 $10\ +\ 3\ =$  

(a)  

 $5\ +\ 8\ =$  

(a)  

 $8\ +\ 6\ =$  

(a)  

 $5\ +\ 11\ =$  

(a)