I don't know how to do area on a shape if it has missing numbers.. .also i need help on division with decimals...
This may help you with the area of different shapes.
http://www.mathsisfun.com/area.html
If you post a specific problem, I'll be glad to help you figure it out.
Study this site for division of decimals.
http://www.mathsisfun.com/dividing-decimals.html
Again -- I'll be glad to help you if you post a specific problem.