Similar to strings, PHP also has a wide array of built-in functions that can be used when working with numbers.

Here’s a list of the commonly used number functions:

abs

Takes a number as an argument and then calculates its absolute value, for example:

echo abs(0 - 10); // Outputs: 10

pow

Raises a number to the power of its exponent.

This function accepts two parameters, the first parameter is the base number and the second parameter is the number that determines how many times that base number will be multiplied by itself, for example:

echo pow(2, 4); // Outputs: 16

sqrt

Takes a number as an argument and then calculates its square root, for example:

echo sqrt(9); // Outputs: 3

fmod

Calculates the remainder (modulo) of the division between two numbers.

This function accepts two parameters, the first parameter is a number which is the dividend and the second parameter is also a number which is the divisor, for example:

echo fmod(10, 6); // Outputs: 4

rand

Generates a random integer.

This function accepts two parameters that are optional, the first parameter is a number which is the lowest possible value and the second parameter is also number which is the highest possible value, for example:

echo rand(); // Outputs: Random integer value
echo rand(10, 30); // Outputs: Random integer value between (and including) 10 and 30

round

Rounds the value of a floating point number.

This function accepts two parameters, the first parameter is a number which is the value to round and the second parameter (which is optional) is the number of digits after the decimal point, for example:

echo round(2.2); // Outputs: 2
echo round(4.6); // Outputs: 5
echo round(5.255499159, 4); // Outputs: 5.2555

ceil

Takes a floating point number as an argument and then rounds it up.

echo ceil(2.4); // Outputs: 3

floor

Takes a floating point number as an argument and then rounds it down.

echo floor(4.8); // Outputs: 4

is_int

Takes a number as an argument and then checks if it’s an integer.

echo is_int(5); // Outputs: 1
echo is_int(5.8); // Outputs:

is_float

Takes a number as an argument and then checks if it’s a floating point number.

echo is_float(5.10); // Outputs: 1
echo is_float(4); // Outputs: 

is_numeric

Takes a value as an argument and then checks if it’s a number.

echo is_numeric(1); // Outputs: 1
echo is_numeric(1.5); // Outputs: 1
echo is_numeric('1'); // Outputs: 1
echo is_numeric('one'); // Outputs: 

With regards to the value returned by the is_int, is_float and is_number functions, take note that 1 means true and that blank means false.

See http://php.net/manual/en/ref.math.php for a complete list of built-in functions that can be used on numbers in PHP.

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This is part 7 of the PHP Basics series.