How to display variables on 0.96" OLED with u8glib library?
The U8glib user reference page mentions a couple of ways to print the value of a number using ASCII characters. 

Eg, following the idea at the second mention of sprintf at above link:

char buf[9];
sprintf (buf, "%d", a);
u8g.drawStr(33, 33, buf);


Edit: The above follows the example at the link, but I've struck it out because in general snprintf is safer than sprintf.  See below.

enum {BufSize=9}; // If a is short use a smaller number, eg 5 or 6 
char buf[BufSize];
snprintf (buf, BufSize, "%d", a);
u8g.drawStr(33, 33, buf);


The other way is via print.  (Search for U8GLIB::print in above link, and also see arduino.cc's Print docs).

Eg:

u8g.print(a);


To get a newline effect, you may need to have a variable keeping track of the current line number; add 1 to it to get next line's number, and use that as a position parameter in a drawStr call.