# Expressions, Operators, and Variable Assignment

We've already described simple examples of assignment, in which a variable is assigned the value of an expression using an equals sign. Most numeric assignments and expressions that work in other high-level languages also work in PHP. Here are some examples:

Assign a value to a variable:

```\$var = 1;
```

Sum integers to produce an integer:

```\$var = 4 + 7;
```

Subtraction, multiplication, and division that might have a result that is a float or an integer, depending on the initial value of \$var:

```\$var = ((\$var - 5) * 2) / 3;
```

These all add 1 to \$var:

```\$var = \$var + 1;
\$var += 1;
\$var++;
```

And these all subtract 1 from \$var:

```\$var = \$var - 1;
\$var -= 1;
\$var--;
```

Multiply to double a value:

```\$var = \$var * 2;
\$var *= 2;
```

Halve a value:

```\$var = \$var / 2;
\$var /= 2;
```

These work with float types too:

```\$var = 123.45 * 28.2;
```

There are many mathematical functions available in the math library of PHP for more complex tasks. We introduce some of these in next pages.

String assignments and expressions are similar:

Assign a string value to a variable:

```\$var = "test string";
```

Concatenate two strings together to produce "test string":

```\$var = "test" . " string";
```

Add a string to the end of another to produce "test string":

```\$var = "test";
\$var = \$var . " string";
```

Here is a shortcut to add a string to the end of another:

```\$var .= " test";
```