How do u do these equations?

First, i would look at the word sum. what does it mean by sum? the sum of two numbers is what? I think of it as sum=its an addition problem and the sum is what those two numbers added together equal. For example the sum of one and two is thee.

Lets say Matt's number is x.

So we got three numbers here; x, 7.5 and 38.2.

how about i simplyfy; "the sum of his number and 7.5 is 38.2"

What it is saying is that...

x and 7.5's sum is 38.2

if sum means it is an addition problem and 38.2 is the answer to this addition problem between 7.5 and x, even though you want to find x... then if you know this, your neext step is to translate this into an equation. 

 x plus 7.5 equals 38.2

x+7.5=38.2.

when it is an equation, you must subtract 7.5 by both sides. so it would be x=38.2-7.5

38.2-7.5 is... 30.7

that means x, Matt's number, is 30.7.

to do some these kinds of problems, you have to translate the sentences into an equation.

when it says the word product it is a multiplication problem

when a number is decreased, it is less than the original amount. so you are subtracting from the original number. so it would be "the number minus lets say 2 is equal to lets say four." that would mean the number is 6. x-2=4 is the equation.

I hope this helped out... I don't have the time to explain everything... this info may help...