Rational Numbers are any numbers that can be written as a ratio of two integers.
Rational came from the word ratio and integers are numbers.
eg. 5 is a rational number because it can be written as 5/1.
1.75 is rational because it can be written as 7/4.
Irrational Numbers numbers that are not rational. ( They can't be made of a ratio of two integers)
eg. The square root of 2 is an irrationable number because it can't be written as a ratio of two integers.
Remember an integer is a whole number. Such as 1, 2, 3, 150687, -45, -4651387