How to express ratio and calculated value for a difference?

I have two piece of plastic. One is .003cm thick, the other is .004cm. I need a ratio to express the difference in thickness, and a calculated value for the difference. How do I go about this?How to express ratio and calculated value for a difference?
Maria,





A ratio will tell how one number is related to another number.





A ratio may be written as A:B or A/B or by the phrase ';A to B';, where A = numerator and B = denominator.





Sample:





3 dogs to 2 kids can be written:





3:2 or 3/2 or 3 to 2.





Your question:





one plastic to another can be written this way:





.003cm: .004cm or this way:





.003cm/.004cm





or this way:





.003cm to .004cm





You need to divide the numerator by the denominator.





.003cm = numerator





.004cm = denominator





Can you take it from here?





Guido