3D Game Programming

10 - 9.5;

// 0.5

23 - 46;

// -23

84 + -42;

// 42

So it even works with negative numbers. Remember this; negative numbers

will be handy as we play with 3D graphics.

OK, so adding and subtracting are pretty easy in JavaScript. What about

multiplication and division? There are plus and minus signs on most key-

boards, but there aren’t × and ÷ keys.

For multiplication, use the asterisk (*) character:

3 * 7;

// 21

2 * 2.5;

// 5

-2 * 4;

// -8

7 * 6;

// 42

Division is done with the slash (/) character:

45 / 9;

// 5

100 / 8;

// 12.5

84 / 2;

// 42

One other thing to know about numbers is that when doing a lot of arithmetic

at the same time, you can use parentheses to group things. The math inside

parentheses is always calculated first:

5 * (2 + 4);

// 30

(5 * 2) + 4;

// 14

Chapter 7. A Closer Look at JavaScript Fundamentals • 70

Prepared exclusively for Michael Powell report erratum • discuss