Year 3 English: Prefixes in-, im-, il- and ir-
Part of the Year 3 English prefixes and suffixes chapter. Chapter overview · whole chapter on one page
Prefixes in-, im-, il- and ir-
The prefix in- means not. Incorrect means not correct, and inactive means not active.
The spelling changes a little before some letters, so that the word is easy to say. Before p, in- becomes im-, as in impossible and impatient. Before l, it becomes il-, as in illegal. Before r, it becomes ir-, as in irregular and irrelevant.
| Prefix | Used before | Example |
|---|---|---|
| in- | most letters | incorrect, inactive |
| im- | p | impossible, impatient |
| il- | l | illegal |
| ir- | r | irregular, irrelevant |
Key ideas
- In- means not. Incorrect means not correct.
- Before p, the prefix is im-: impossible, impatient.
- Before l, the prefix is il-: illegal.
- Before r, the prefix is ir-: irregular, irrelevant.
Method. Match the meaning to the word, then check its spelling.
- Read the meaning. Think about what the clue describes.not right; wrong
- Find the word that matches. Think of the one word with this meaning.incorrect
- Check the spelling. In- means not: incorrect means not correct.Tricky part: in
- Write the answer. incorrect
Check. Read incorrect and check each letter against the word. ✓
Watch out. In- means not: incorrect means not correct.
Method. Think what the sentence means, then choose the word that fits the gap and its spelling.
- Read the sentence with the gap. Think what the sentence means.It is ___ to see the wind, but we can see the leaves move.
- Find the word that fits the meaning. not able to happen or be doneimpossible
- Put the word in the gap. Read the sentence again. It makes sense.It is impossible to see the wind, but we can see the leaves move.
- Write the answer. impossible
Check. Read the whole sentence with impossible in it. ✓
Watch out. In- becomes im- before p, as in impossible.
Method. Say the whole word, then fill the box with the tricky letters.
- Say the whole word. Read every letter in order.illegal
- Look at the empty box. The box stands for 2 letter(s) in a row.2 missing letter(s)
- Write the missing letters. In- becomes il- before l, as in illegal.il
Check. Put il back in the box and read illegal. ✓
Watch out. In- becomes il- before l, as in illegal.
Watch out
Watch out: do not write inpossible or inlegal. The n changes to m before p, and to l before l. Say the root word first, then check which letter comes next.
Exam tip
Grown-up tip. Say the root word, such as possible, then add the prefix. Ask your child which letter the root word starts with, and whether the n needs to change.
Exercise 2B Practice: in-, im-, il- and ir-
Method. Match the meaning to the word, then check its spelling.
- Read the meaning. Think about what the clue describes.not right; wrong
- Find the word that matches. Think of the one word with this meaning.incorrect
- Check the spelling. In- means not: incorrect means not correct.Tricky part: in
- Write the answer. incorrect
Check. Read incorrect and check each letter against the word. ✓
Watch out. In- means not: incorrect means not correct.
Method. Match the meaning to the word, then check its spelling.
- Read the meaning. Think about what the clue describes.not moving or doing anything
- Find the word that matches. Think of the one word with this meaning.inactive
- Check the spelling. In- means not: inactive means not active.Tricky part: in
- Write the answer. inactive
Check. Read inactive and check each letter against the word. ✓
Watch out. In- means not: inactive means not active.
Method. Match the meaning to the word, then check its spelling.
- Read the meaning. Think about what the clue describes.not willing to wait calmly
- Find the word that matches. Think of the one word with this meaning.impatient
- Check the spelling. In- becomes im- before p, as in impatient.Tricky part: im
- Write the answer. impatient
Check. Read impatient and check each letter against the word. ✓
Watch out. In- becomes im- before p, as in impatient.
Method. Match the meaning to the word, then check its spelling.
- Read the meaning. Think about what the clue describes.not allowed by the law
- Find the word that matches. Think of the one word with this meaning.illegal
- Check the spelling. In- becomes il- before l, as in illegal.Tricky part: il
- Write the answer. illegal
Check. Read illegal and check each letter against the word. ✓
Watch out. In- becomes il- before l, as in illegal.
Method. Think what the sentence means, then choose the word that fits the gap and its spelling.
- Read the sentence with the gap. Think what the sentence means.The jigsaw was ___ because one piece was lost.
- Find the word that fits the meaning. not finished; with some parts missingincomplete
- Put the word in the gap. Read the sentence again. It makes sense.The jigsaw was incomplete because one piece was lost.
- Write the answer. incomplete
Check. Read the whole sentence with incomplete in it. ✓
Watch out. In- means not: incomplete means not complete.
Method. Think what the sentence means, then choose the word that fits the gap and its spelling.
- Read the sentence with the gap. Think what the sentence means.It is ___ to see the wind, but we can see the leaves move.
- Find the word that fits the meaning. not able to happen or be doneimpossible
- Put the word in the gap. Read the sentence again. It makes sense.It is impossible to see the wind, but we can see the leaves move.
- Write the answer. impossible
Check. Read the whole sentence with impossible in it. ✓
Watch out. In- becomes im- before p, as in impossible.
Method. Think what the sentence means, then choose the word that fits the gap and its spelling.
- Read the sentence with the gap. Think what the sentence means.The bus times were ___, so we waited a long time.
- Find the word that fits the meaning. not even, or not following the usual patternirregular
- Put the word in the gap. Read the sentence again. It makes sense.The bus times were irregular, so we waited a long time.
- Write the answer. irregular
Check. Read the whole sentence with irregular in it. ✓
Watch out. In- becomes ir- before r, as in irregular.
Method. Think what the sentence means, then choose the word that fits the gap and its spelling.
- Read the sentence with the gap. Think what the sentence means.Mum found a bag that was ___ but still well made.
- Find the word that fits the meaning. not costing much moneyinexpensive
- Put the word in the gap. Read the sentence again. It makes sense.Mum found a bag that was inexpensive but still well made.
- Write the answer. inexpensive
Check. Read the whole sentence with inexpensive in it. ✓
Watch out. In- means not: inexpensive means not expensive.
Method. Say the whole word, then fill the box with the tricky letters.
- Say the whole word. Read every letter in order.impatient
- Look at the empty box. The box stands for 2 letter(s) in a row.2 missing letter(s)
- Write the missing letters. In- becomes im- before p, as in impatient.im
Check. Put im back in the box and read impatient. ✓
Watch out. In- becomes im- before p, as in impatient.
Method. Say the whole word, then fill the box with the tricky letters.
- Say the whole word. Read every letter in order.irrelevant
- Look at the empty box. The box stands for 2 letter(s) in a row.2 missing letter(s)
- Write the missing letters. In- becomes ir- before r, as in irrelevant. It means not relevant.ir
Check. Put ir back in the box and read irrelevant. ✓
Watch out. In- becomes ir- before r, as in irrelevant. It means not relevant.
Method. Compare the wrong spelling with the word we want.
- Look at inlegal. Compare it with the word illegal.inlegal is not right
- Find the tricky part. In- becomes il- before l, as in illegal.Tricky part: il
- Write the word correctly. illegal
Check. Read illegal and check each letter. ✓
Watch out. In- becomes il- before l, as in illegal.
Method. Compare the wrong spelling with the word we want.
- Look at inpossible. Compare it with the word impossible.inpossible is not right
- Find the tricky part. In- becomes im- before p, as in impossible.Tricky part: im
- Write the word correctly. impossible
Check. Read impossible and check each letter. ✓
Watch out. In- becomes im- before p, as in impossible.
Method. Compare the wrong spelling with the word we want.
- Look at inregular. Compare it with the word irregular.inregular is not right
- Find the tricky part. In- becomes ir- before r, as in irregular.Tricky part: ir
- Write the word correctly. irregular
Check. Read irregular and check each letter. ✓
Watch out. In- becomes ir- before r, as in irregular.
Method. Look at the letter the root word starts with.
- Look at inactive. Active starts with a, so the prefix is in-.in + active
- Look at impatient. Patient starts with p, so in- becomes im-.im + patient
- Write the answer. No. Inactive uses in-, because active starts with a. Impatient uses im-, because patient starts with p.
Check. The prefix depends on the first letter of the root word. ✓
Watch out. Check the first letter of the root word.
Method. Look at the first two letters of each word.
- Look at illegal. It starts with il-.il-
- Look at irregular. It starts with ir-, because regular starts with r.ir- + regular
- Write the answer. irregular
Check. Regular starts with r, so the prefix is ir-. ✓
Watch out. The prefix changes before l, r and p.
Method. Use each word in a sentence that makes sense.
- Use incomplete. Incomplete means not finished.The puzzle is incomplete.
- Use illegal. Illegal means not allowed by the law.It is illegal to light fires here.
- Write the answer. Any two correct sentences, for example: The puzzle is incomplete. It is illegal to light fires here.
Check. Check each prefix. ✓
Watch out. Check the letter after the prefix.
Method. Look at the letters after the prefix.
- Find the in- word. incorrect starts with in- before c.incorrect
- Find the im-, il- and ir- words. impossible has im-, illegal has il-, and irregular and irrelevant have ir-.impossible, illegal, irregular, irrelevant
- Write the answer. in-: incorrect. im-: impossible. il-: illegal. ir-: irregular, irrelevant.
Check. Each word is in the right list. ✓
Watch out. Check the first letter of the root word.
Method. Think what the sentence means, then choose the word that fits the gap and its spelling.
- Read the sentence with the gap. Think what the sentence means.The old volcano has been ___ for many years.
- Find the word that fits the meaning. not moving or doing anythinginactive
- Put the word in the gap. Read the sentence again. It makes sense.The old volcano has been inactive for many years.
- Write the answer. inactive
Check. Read the whole sentence with inactive in it. ✓
Watch out. In- means not: inactive means not active.
Method. Look at what the prefix means.
- Look at inexpensive. In- means not, so inexpensive means not expensive.in + expensive
- Think what not expensive means. Something that is not expensive costs little money.cheap
- Write the answer. No. In- means not, so inexpensive means not expensive, which is cheap.
Check. Inexpensive means cheap. ✓
Watch out. Expensive means costing a lot of money.