Place value chart
Rational numbers are numbers that can be written as a ratio, which means it can be written as a fraction, in which the numerator and the denominator are both whole numbers.
Irrational numbers are numbers that can't be ratios or fractions, Pi is a great example π = 3.1415926535897932384626433832795 (and more...) . You cannot write down a simple fraction that equals Pi.
Percentage review 1.1
Buying and selling 1.2