The best way to think about equivalent fractions is that they are fractions that have the same overall value. Equivalent fractions represent the same part of a whole. For example, if we cut a pie exactly down the middle, into two equally sized pieces, one piece is the same as one half of the pie.
And if another pie (the same size) is cut into 4 equal pieces, then two pieces of that pie represent the same amount of pie that 1/2 did. So we can say that 1/2 is equivalent (or equal) to 2/4.