Two fractions are equivalent if
(a) Both the numerator (top) and denominator (bottom) of each fraction are the same. For example, two-fifths (2/5) of one thing is equivalent to two-fifths (2/5) of another thing.
(b) The numerator and denominator of one fraction can both be multiplied by the same number to equal the numerator and denominator of the other fraction. An example of this would be two-thirds (2/3) and six-ninths (6/9). Both two and three can be multiplied by three (3) to equal the numbers in their respective spots in the fraction six-ninths (6/9). (Two multiplied by three is six, three multiplied by three is nine.)
OR
(c) The numerator and denominator of one fraction can be divided by the same number to equal the numerator and denominator of the other fraction, like with six-tenths (6/10) and three-fifths (3/5). Both six and ten, when divided by two, are equal to three and five, respectively.