There are 5 different set of fractions that help students think through and understand key concepts about fractions in relation to one another.
The first set I introduce with the unit fractions.
Then there are 2 sets that compare like denominators (1/4's and then 1/6's).
Then the last 2 sets are with unlike denominators.
I introduce a new set each day as whole group when I teach comparing and ordering fractions and I let students complete them in pairs during math centers.