$349\ -\ 100\ =$  

(a)  

 $648\ -\ 306\ =$  

(a)  

 $2493\ -\ 1272\ =$  

(a)  

 $267\ -\ 86\ =$  

(a)  

 $761\ -\ 348\ =$  

(a)  

 $1647\ -\ 478\ =$  

(a)  

 $4652\ -\ 1257\ =$  

(a)  

 $8642\ -\ 3945\ =$  

(a)  

 $6452\ -\ 4839\ =$  

(a)