# PHP Numbers

There are two types of number in PHP, namely, integers and floating point numbers, also known as “floats”.

## Integer

An integer is a whole number like 1, 2 and 3 as well as -1, -2 and -3.

## Floating Point Number

A floating point number is a number that has a decimal in it followed by a number of significant digits like 2.5 or -4.202.

Example code:

``````\$var1 = 1; // Integer
\$var2 = 2.5; // Floating Point Number

echo ((1 + 5 + \$var1) * \$var2) / 2 - 3; // Outputs: 5.75
``````

Take note that in PHP, basic math rules like the parentheses and the order of operations between multiplication, division, addition and subtraction still applies.

Therefore…

• `1 + 5 + \$var1` will be evaluated first which returns 7.
• 7 gets multiplied by the value of `\$var2` which returns 17.5.
• 17.5 gets divided by `2` which returns 8.75.
• 8.75 gets subtracted by `3` which would then return 5.75.

## Incrementing/Decrementing a value

If you combine addition, subtraction, multiplication or division with the value assignment operator, you can either increment or decrement a number, for example:

``````\$var1 = 1;
\$var2 = 10;
\$var3 = 2;
\$var4 = 20;

echo \$var1 += 2; // Outputs: 3
echo \$var2 -= 5; // Outputs: 5
echo \$var3 *= 2; // Outputs: 4
echo \$var4 /= 2; // Outputs: 10
``````

The above code can also be written in a much longer format like so:

``````\$var1 = 1;
\$var2 = 10;
\$var3 = 2;
\$var4 = 20;

echo \$var1 = \$var1 + 2; // Outputs: 3
echo \$var2 = \$var2 - 5; // Outputs: 5
echo \$var3 = \$var3 * 2; // Outputs: 4
echo \$var4 = \$var4 / 2; // Outputs: 10
``````

If you only need to increment or decrement a number by 1, use `++` or `--` instead, for example:

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

\$var++;
echo \$var; // Outputs: 2

\$var--;
echo \$var; // Outputs: 1
``````

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This is part 6 of the PHP Basics series.

Written on July 27, 2018