While working with numbers in ruby, there are only 2 classes that the values belong to. One will be a Fixnum class and other would be a Float class. Any value either positive or negative integer belong to Fixnum class and if the value has a decimal point it belongs to Float class
Given below are few variables assigned to numbers

num1 = 10
num2 = 12.8
num3 = 18.2
num4 = 2

We can see that

num1.class # returns Fixnum
num2.class # returns Float

When we use numbers in a program, we generally perform arithmetic operations of them. All the regular arithmetic operators can be used on numbers in ruby like the +, -, / ,* & %
Here (+) is for addition, (-) is for subtraction, (*) is for multiplication,( /) is for division, (%) is known as a modulo operator, when modulo  operator is used it returns the remainder ie.
10 % 3 # gives us 1

num1 + num4 => 12
num2 + num3 => 31
num2 – num1 => 2.8
num1 / num2 => 2
num1 * num2 => 20

Number Methods

num2.round # 13
Num3.round # 18
Num3.ceil # 19
Num2.floor # 12
(-123).abs # 123 abs returns the absolute value

Type conversions in Ruby
num1.to_f # 10.0
num2.to_i # 12
Num3.to_s # “18.2”

Num1.odd? # false
Num1.even? # true

( note – any method ending with ? is known as a Boolean method in ruby, the return value will always either true or false )