5th grade absorbed prefixes (im-, il-, ir-) worksheets
Fifth graders sort not-words by their absorbed prefix: im- (impossible, impatient), il- (illegal, illogical), ir- (irregular, irresponsible), and learn that all three are in- shape-shifted to match the base word.
Free printable PDF worksheet, aligned to Common Core L.5.4.b.
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The kind of words you'll complete and sort
Fill in the missing letters to make a real word, then write the whole word in its column.
lustrateperfectluminatereversiblepossiblerationalmobilelegiblerelevant
Columns: im- and il- and ir-. Only im turns "_perfect" into a real word, so imperfect goes under im-; Only il turns "_lustrate" into a real word, so illustrate goes under il-; Only ir turns "_reversible" into a real word, so irreversible goes under ir-.
Every print pulls a fresh set of word lists at this level, so a make-up test or a second sibling never gets the same sheet.
What's on each sheet
- Complete and sort. Fill in the missing letters to make a real word, then write the whole word in its column. 21 words per page.
Every version prints on US Letter or A4, with its answer key on the last page.
How to teach this
Do prefix surgery: write in- + legal, then show the n absorbing into l. The double letter appears before your child's eyes, and a spelling mystery becomes a mechanical fact. Repeat with in+possible and in+regular.
Watch for: All three prefixes are the same prefix, in-, wearing camouflage. Only the spelling changes to match the next letter; the meaning rides along untouched. The absorption explains the double letters kids find mysterious: illegal has two l's because in+legal fused. Seeing the seam makes the spelling logical instead of random.
Common questions about absorbed prefixes (im-, il-, ir-)
- What is an absorbed prefix?
- A prefix that changes its last letter to blend with the word it joins: in- becomes im- before p or m, il- before l, ir- before r. The prefix keeps its meaning, usually not, sometimes in or into, while only the spelling absorbs.
- Why does this create double letters?
- The absorbed letter doubles with the base word's first letter: in+legal makes illegal, in+regular makes irregular. The seam explains spellings kids otherwise have to memorize blind.
Related worksheets
- 6th grade absorbed prefixes (im-, il-, ir-) A step harder, same skill
- 5th grade adages and proverbs Same grade, nearby skill
- 5th grade analogies Same grade, nearby skill
- 5th grade connotation and denotation Same grade, nearby skill
- Absorbed prefixes (im-, il-, ir-), all grades The full progression
- All 5th grade English worksheets Every skill at this level
- All 5th grade worksheets Everything at this level
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Aligned to Common Core L.5.4.b. Reviewed by the One more sheet team. Content version 179, updated August 2026.
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