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Lesson 127

uni-, bi-, tri-

The prefix UNI- means one, BI- means two, and TRI- means three

Be sure students do not confuse the prefixes UNI- and UN-. For example, in the word unimpressed, the prefix being used is UN- meaning not, not UNI- meaning one. Be sure students do not confuse the prefixes BI- and BIO-. For example, in the word biology, the prefix being used is BIO- meaning life, not BI- meaning two.

Today's plan

about 15 min
  1. Step 1Warm up our ears (blend & segment)2 min
  2. Steps 2 & 3Look & Say / Listen & Spell4 min
  3. Step 4Blending drill3 min
  4. Step 5New concept + read/spell6 min
Step 1

Warm Up Our Ears

Say the sounds; students blend them into a word. Then say a word; students break it apart.

Blend it (teacher says sounds → you say word)

/y/ · /o͞o/ · /n/ · /ə/ · /f/ · /ī/unify
/y/ · /o͞o/ · /n/ · /ə/ · /k/ · /or/ · /n/unicorn
/t/ · /r/ · /i/ · /p/ · /ə/ · /l/triple

Break it (I say word → you say sounds)

Steps 2 & 3

Flashcard Drills

Full-screen cards for the class. Tap a card to check the answer, or press Hear the words to hear the example words read aloud.

Step 4

Blending Drill

Change one part at a time and read the new word.

Step 5

New Concept

Today we learn three new prefixes: UNI-, BI-, and TRI-.

Highlighted words are the ones to show and practice reading — tap one to hear it.

Prefixes are added to the beginning of a word to change the word's meaning. Today we will learn three new prefixes: UNI-, BI-, and TRI-. UNI-: UNI- means one. The U in UNI- makes the long /yo͞o/ sound and the I makes the schwa sound /ə/, as in . BI-: BI- means two. The I in BI- makes the long /ī/ sound, as in . TRI-: TRI- means three. The I in TRI- usually makes the long /ī/ sound, as in but sometimes makes the short /i/ sound, as in .

uni-, bi-, tri-

We can remember what these prefixes mean by adding each prefix to the base cycle. A unicycle has one wheel, a bicycle has two wheels, and a tricycle has three wheels.