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PHP Numbers
Order of Operations

We can chain multiple operations together to get a single result:

``````echo 2 + 3 + 4 + 5 - 1.1; // Prints: 12.9
echo 2 * 9 / 6; // Prints: 3``````

You might have learned about operations having an order of precedence in a math class. This means that operations in a chain aren’t simply performed from left to right; rather each operator is given a special rank.

Operations will be evaluated in the following order:

1. Any operation wrapped in parentheses (`()`)
2. Exponents (`**`)
3. Multiplication (`*`) and division (`/`)
4. Addition (`+`) and subtraction (`-`).

The acronym PEMDAS can be helpful for remembering the order of precedence for these arithmetic operations.

``echo 1 + 3 * 9; // Prints: 28``

In the example above, `3 * 9` (27) is calculated first and then is added to 1 to yield a final result of 28. We can change what this expression returns by using parentheses:

``echo (1 + 3) * 9; // Prints: 36``

Here, `1 + 3` (4) is calculated first and then that value is multiplied by 9 to which returns 36.

Let’s practice writing some chained operations!

### Instructions

1.

Heya! Can you help me out. Use `echo` to print the answer to the terminal.

I’m trying to figure out how much money I should have. At the start of the day I had \$94.

• I spent \$4.25 on coffee
• A friend gave me \$7 that he owed me
• I went out for a meal. The bill was \$23.50, but I also gave a 20% tip.
• Some friends and I found \$20 on the ground and split it four ways

I think that’s everything.

Use a single chained operation to get your result!