Rational numbers terminate (1,2,3,....) or repeat (1/3 or .3333333...). Irrational numbers never terminate or repeat. Perhaps the most common irrational number is Pi. Additionally, the square root of any number that is not a perfect square is irrational (square root of 2, square root of 3, square root of 5, etc.)

Rational comes from the root word ratio. This means they are fractions. This includes the whole numbers (0,1,2,3....) and the integers which are the whole numbers and their opposites (...-3,-2,-1,0,1,2,3...) which can all be written over one to make a fraction. (0/1=0, 1/1=1, 2/2=2, -1/1=-1, -2/1=-2, etc.)

Rational comes from the root word ratio. This means they are fractions. This includes the whole numbers (0,1,2,3....) and the integers which are the whole numbers and their opposites (...-3,-2,-1,0,1,2,3...) which can all be written over one to make a fraction. (0/1=0, 1/1=1, 2/2=2, -1/1=-1, -2/1=-2, etc.)