It looks like maybe you need to go back and take a course in PRE-algebra.
Question: What is the value of the expression
If you answered 35, then indeed it is time to go back to junior high school, at least.
Multiplication has a higher precedence
than addition. So the correct value of that expression is 23
That is, you must do the multiply (4*5) first and *THEN* do the addition.
So now look at your code:
total = deals + 2500 * 0.01
The multiply will take place first (2500 * 0.01, giving you 25) and then the addition, so your total
will always be just 25 more than deals
(And that assumes you read what Philip wrote and converted deals
to a number before trying to add to it.)