1. 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

2. con-
with, together Ex. conjoin conjunction connect _______________

3. de-
from, reverse
Ex. detach
deflate
detour
______________

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

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

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

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

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

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

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

11. 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

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

13. 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

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

15. Let’s continue with more prefixes

16. sub-
under Ex. submerge subway submarine _____________

17. pre-
before Ex. preheat precede prehistoric _____________

18. cent-
a hundred Ex. centipede century centimeter _____________

19. anti-
against Ex. antivirus antifreeze anti-bullying ____________

20. multi-
many Ex. mulitlingual multipurpose multicolored ____________

21. uni-
one Ex. unicorn unidirectional unicycle ____________

22. mis-
wrongly Ex. misunderstood misspelled misbehave ____________

23. non-
not Ex. nonstop nonfiction nonviolent ____________

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

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

26. 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

27. 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

28. 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.

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

30. This Prefix PPT was created by: Cristina de Cardenas 2012