Equivalent fractions are fractions that are expressed in a different way from each other but have the same value. An excellent method of explaining this to kids is through the use of money. Or, a more traditional 'classroom' manipulative is either using a set of Fraction Circles or Fraction Bars.
I use American dollars in this example, however any currency works just the same! Even if your child in someway or completely understands this concept, it will just solidify their understanding. This works really well for kids that lean toward any of the three main learning styles.
...either in two groups on the table or the note in one hand and the coins in the other.
Now ask them a few questions ....
Which pile has the most of ANY ONE thing?...The answer here is 'quarters' there are four and only one dollar bill.
Which pile has the most VALUE?...The answer here is they both have the same value - $1.00
How can 1 of something and 4 of something else have the same value?
Because they are composed of the same thing - 100 pennies, but are represented in two different ways.
They are EQUIVALENT to each other.
Knowing a skill is the first step, the second must always be to practice. Head to my fractions worksheets to do this.