Watch "BALANCING EQUATIONS" and try activities (needs Flash/ won't work on Apple products)

http://www.learnalberta.ca/content/mesg/html/math6web/index.html?page=lessons&lesson=m6lessonshell11.swf

In textbook p.33-34  andp.35 Q.  1-5

Also p.36-38 Q.1-5