The note
How schools teach it now
Schools teach a 'root word' plus prefixes and suffixes added to it. KS2 prefixes include un-, dis-, mis-, in-, re-, sub-, inter-, super-, anti- and auto-. In- becomes il- before l (illegal), im- before m or p (impossible) and ir- before r (irregular).
5-minute kitchen-table activity
Make a prefix wall on the fridge: write un, dis, im, il and ir on sticky notes, and happy, agree, possible, legal and regular on others. Your child matches each pair and reads the new word aloud. Hearing it helps: 'illegal' sounds right, 'unlegal' doesn't.
Worked example
Which prefix makes the opposite of 'responsible'? (un, dis, im, in, ir)
- The word begins with r.
- Before r, in- becomes ir- (irregular, irrelevant).
- Say it to check: irresponsible.
Answer: ir (irresponsible)
Common mistakes to watch for
- Dropping a letter: 'irelevant', 'ilegal'. The prefix keeps its own letter, giving rr or ll.
- Using 'un' for every opposite because it is the most common.
- Thinking every word starting with dis or im has a prefix (dish, imagine).
Encouragement
- Try saying
- “Let's split the word into parts and see what each bit does.”
- Rather than
- “Just learn which prefix goes with which word.”