[VE][html5] Add Subject Here

The site I am checking: http://webshare.hkr.se/MABO0118/ip1ht13/iu1/dokumentformatering.html 


When i validate is says that i have one error that says: 

Error Line 18, Column 8: The center element is obsolete. Use CSS instead. <center>
 
How should I fix this? 

I want all the text until the table to be centered. 



Error [html5]: ""
NOTE: Whenever possible, give the address of the document you were checking.