Once children can recognise basic fractions, they must then be able to say which fractions are the same size as each other i.e. equivalent. e.g. 1/2 is the same size as 2/4 or 3/6 or 12/24 etc.
The basic trick, which childen need to grasp, in order to find equivalent fractions, is that if they multiply the numerator and denominator by the same number, the new fraction will be equivalent to the old one. e.g. if you have 3/4 and multiply the numerator by 3 and the denominator by 3 you will end up with 9/12. This is because:- 3 x 3 = 9, 4 x 3 = 12 so 3/4 and 9/12 are equivalent.
Therefore finding equivalent fractions is really just practising children's table knowledge, for all they are really doing is multiplying the top and bottom of the fraction by the same number, which is why I often use it as a mental warm up. I will ask, "What fraction is the same size as 3/8?" They will then multiply the numerator and denominator by the same figure and get 6/16, 9/24, 15/40, 30/80 etc. They can thus easily practise this at home, for all you have to do is ask, "Can you give me three fractions the same size as 4/5?" or 5/6, or 5/9 etc.
I have included a worksheet which you can print off which deals with equivalent fractions, and as usual it includes a blank, which can also be printed if they require more help.