Teaching kids about plurals can be tricky as there are so many different rules, exceptions to the rules and it just goes to show that our language is hard.
This pack may help your kids with plurals by creating interactive note pages so they can go back and refer to a source that has some words to help them.
These 'I have, who has' cards will help consolidate their thinking as well.
There are also some recording sheets to help define and illustrate plurals too.