Posted by David on Tuesday, December 8, 2009 at 4:58pm.
The sum of two decimal numbers is 5.3. Their difference is 1.7, and their product is 6.3. What are the two numbers?
Does the product have anything to do with getting the answers?

Math  6th Grade  drwls, Tuesday, December 8, 2009 at 5:04pm
You don't need the product info to solve this. You only need to write two equations to solve for two unknowns.
a + b = 5.3
a  b = 1.7
2a = 7
a = 3.5
b = 5.3  3.5 = 1.8
The product a*b does satisfy the 6.3 requirement. If it didn't, there would be no solution to all three requirements. 
Math  6th Grade  David, Tuesday, December 8, 2009 at 5:07pm
Thank you drwls!

Math  6th Grade  drwls, Tuesday, December 8, 2009 at 6:27pm
I should not be using algebra for a sixth grade question. It's really the quickest way I know. I hope you were able to follow that.