N/8+4=28. 
This is how you write out this equation.
        
             
        
        
        
Answer:
The atomic mass
Step-by-step explanation:
The decimal at the bottom of an element represents how much one atom of that element weighs. 
 
        
                    
             
        
        
        
Answer:
144 days
Step-by-step explanation:
160 · 0.9
 
        
             
        
        
        
Answer:
where is the diagram or the explanation of the circle?