# FAQ: Learn Java: Manipulating Variables - Multiplication and Division

This community-built FAQ covers the “Multiplication and Division” exercise from the lesson “Learn Java: Manipulating Variables”.

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This exercise can be found in the following Codecademy content:

## FAQs on the exercise Multiplication and Division

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This lesson assumes everyone knows how to calculate percentages. I didn’t know how to do this without looking it up. For this exercise, what is meant by ‘tax’ is the tax rate percentage (.0875), NOT the actual total amount of tax someone is paying. Thus, the total amount of tax being paid needs to be calculated ex. subtotal*tax

The lesson also doesn’t teach if there are any rules regarding calculating multiple numbers together at once so I just had to guess that they could all be calculated together.

Solution for instruction 1. : double total = subtotal + subtotal*tax;
System.out.println (total);

12 Likes

The lesson doesn’t teach that you can do multiple operations at once; or even that you can use parantheses to override order of operations if needed, which is what you should do in this case (not needed, but definitely would make more sense). Change the question, maybe make it subtotal + tip instead of tax

1 Like

Thank you for you comment. I’m in the same boat when it comes to calculating percentages and your comment really clarified the assignment. They did a poor job with this one.

1 Like

The lesson states “product of” which is multiplying. Gotta remember that next time!

2 Likes

Very sloppy work on this page. Alot of assumptions and not at all clear.

I hope someone sees this comment and revises this exercise.

public class MultAndDivide {

public static void main(String args) {

``````double subtotal = 30;

double tax = 0.0875;

double total = subtotal + subtotal*tax;

System.out.println(total);

double perPerson = total/4;

System.out.println(perPerson);
``````

}

}

Here’s another way to calculate total w/ tax (same result, of course):

`subtotal * ( 1 + tax )`