---
title: Ruby Number Methods
---
Ruby provides a variety of built-in methods you may use on numbers. The following is an incomplete list of integer and float methods.
## Even:
Use `.even?` to check whether or not an **integer** is even. Returns a `true` or `false` **boolean**.
```Ruby
15.even? #=> false
4.even? #=> true
```
## Odd:
Use `.odd?` to check whether or not an **integer** is odd. Returns a `true` or `false` **boolean**.
```Ruby
15.odd? #=> true
4.odd? #=> false
```
## Ceil:
The `.ceil` method rounds **floats** **up** to the nearest number. Returns an **integer**.
```Ruby
8.3.ceil #=> 9
6.7.ceil #=> 7
```
## Floor:
The `.floor` method rounds **floats** **down** to the nearest number. Returns an **integer**.
```Ruby
8.3.floor #=> 8
6.7.floor #=> 6
```
## Next:
Use `.next` to return the next consecutive **integer**.
```Ruby
15.next #=> 16
2.next #=> 3
-4.next #=> -3
```
## Pred:
Use `.pred` to return the previous consecutive **integer**.
```Ruby
15.pred #=> 14
2.pred #=> 1
(-4).pred #=> -5
```
## To String:
Using `.to_s` on a number (**integer**, **floats**, etc.) returns a string of that number.
```Ruby
15.to_s #=> "15"
3.4.to_s #=> "3.4"
```
## To Float:
Converts an Integer to a Float.
```Ruby
15.to_f #=> 15.0
```
## Absolute value:
Returns the absolute value of the integer.
```Ruby
-12345.abs #=> 12345
12345.abs #=> 12345
```
## Greatest Common Denominator:
The `.gcd` method provides the greatest common divisor (always positive) of two numbers. Returns an **integer**.
```Ruby
15.gcd(5) #=> 5
3.gcd(-7) #=> 1
```
## Round:
Use `.round` to return a rounded **integer** or **float**.
```Ruby
1.round #=> 1
1.round(2) #=> 1.0
15.round(-1) #=> 20
```
## Times:
Use `.times` to iterate the given block ```int``` times.
```Ruby
5.times do |i|
print i, " "
end
#=> 0 1 2 3 4
```