Answer:
10/18 
Step-by-step explanation:
3/18 +7/18 =10/18 
 
        
             
        
        
        
She simplified it wrong because you're only supposed to simplify it with the same numbers. For example: simplify 2/4. You divide it by 2/2. You do the same and it will be correct.
        
                    
             
        
        
        
Answer:
.
Step-by-step explanation: