Part of a whole.In a fraction, the denominator tells us how many parts the whole is divided into, and the numerator tells us how many of those parts we're dealing with. Example: 3/4. Here 3 is a numerator and 4 is the denominator.
Proper fraction: Numerator is less than the denominator.
Improper fraction: Numerator is greater than or equal to denominator.
Equivalent fractions: Fractions that represent the same number.
Reciprocal: The multiplicative inverse of a number. For a fraction, it's obtained by "turning the fraction over". This means, that a reciprocal is obtained by making the reversing the values of numerator and denominator.