A fraction is a number of the form ±a/b, where a and b are positive integers. The number a is called the numerator and b is called the denominator. The numerator tells you the number of equal parts, and the denominator tells you how many of those parts make up a whole. Often fractions are numbers that fall between integers. Fractions are also used to show division.
3/5 of the cake means 3 pieces of a cake which is divided into 5 equal pieces.
The fraction 7/4 is a number between 2 and 3.
6x/2 = 6x ÷ 2 = 3x
If a fraction’s numerator and denominator are equal (e.g. 5/5) the fraction is equal to 1.
(All 5 pieces of a cake that is cut into 5 pieces is 1 whole cake.)
A fraction that has zero as its numerator (e.g. 0/5) is equal to zero. (Zero pieces of the cake that is cut into 5 pieces.)
A fraction that has zero as its denominator (e.g. 8/0) is undefined.
Note: On the GMAT, fractions may be shown in either of two formats. You will need to understand both.
Fractions can be on one line, like
3/5 = (x+2)/10
They can also be “built up,” like:
3/5 = x+2/10