WHEN ubuntu don't accept

While writing my first C code using math library on XUbuntu I faced problem,

which says undefined reference to pow, at a time I was making number ^ power 

Program.

So while searching I got to know that you have to do this while compiling in terminal 

Eg ->    gcc  filename.c  -lm

By adding -lm after gcc filename.c we can easily compile the program using math.h library.