A phoneme is a unit of sound. The 'er' phoneme sounds like this:
Sometimes the 'er' phoneme is spelt in different ways. The other main ways of spelling the phoneme are 'ur' and 'ir'.
Sometimes if the sound comes after the letter 'w' it can even be spelt 'or'.
In this worksheet you can practise reading and writing these different spellings of the 'er' phoneme.