Letters added at the beginning of a root word to change its meaning Prefixes: Letters added at the beginning of a root word to change its meaning

con- with, together Ex. conjoin conjunction connect _______________

de- from, reverse Ex. detach deflate detour ______________

ex- out, former, beyond Ex. exhale ex-husband extraterrestrial _______________

dis- not, opposite of Ex. dislike dishonest disconnect _____________

im- not, opposite of Ex. improper impossible immature _____________

in- not, opposite of Ex. inconsistent incompetent incomplete _____________

un- not, opposite of Ex. unequal unable unzipped _____________

Let’s Practice If certain means “sure,” then uncertain means: beyond sure with sure from sure not sure

The answer is d because the prefix “un” means not. certain = sure uncertain = not sure

Let’s Practice If the prefix con means with or together, what does consensus most likely mean: Your sense of smell is well developed to make a decision with a group having a lot of money studying hard for a test

Answer The answer is b. con = together sensus = latin root meaning to think or understand consensus = making a decision together as a group

Let’s Practice If the word increase means to grow in an upward fashion, then decrease probably means: to grow faster to grow slower to shrink get rid of creases

Answer The answer is c. de=means reverse increase = to grow decrease = to shrink

Let’s continue with more prefixes

sub- under Ex. submerge subway submarine _____________

pre- before Ex. preheat precede prehistoric _____________

cent- a hundred Ex. centipede century centimeter _____________

anti- against Ex. antivirus antifreeze anti-bullying ____________

multi- many Ex. mulitlingual multipurpose multicolored ____________

uni- one Ex. unicorn unidirectional unicycle ____________

mis- wrongly Ex. misunderstood misspelled misbehave ____________

non- not Ex. nonstop nonfiction nonviolent ____________

Let’s Practice What does the word subzero probably mean: below zero a number replacing zero a large 12” sandwich underground

The answer is a. sub = under or below subzero = below zero

Let’s Practice What does the word centiliters probably mean: Not able to litter a liter full of pennies one hundred letters sent together a metric unit of volume equal to one hundredth of a liter

Answer The answer is d. centi = a hundred liter = a metric unit of volume centiliter = A metric unit of volume equal to one hundredth of a liter

In conclusion Prefixes are letters added at the beginning of a root word to change its meaning. Knowing what prefixes mean will help you better understand the meaning of unknown words.

You are now on your way to becoming a prefix expert! Congratulations You are now on your way to becoming a prefix expert!

This Prefix PPT was created by: Cristina de Cardenas 2012