First let's explain what a rational and irrational numbers are;
Rational numbers are numbers that can be expressed as a ratio of two integers but the denominator must not be zero
Rational numbers can be negative or positive.
Rational numbers have a terminating decimals.
e.g 5 can be express as 10/2 , there fore 5 is a rational numbers
1.5 can be express as 3/2 , therefore 1.5 is a rational number
Irrattional numbers are numbers that cannot be express as fraction and they have unending decimals
Example
π that has a value of 3.141592653589…….
-2 + 15 = 13
13 is a rational number
Therefore it is a rational number