IWP Week 1 — Number Roots

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The Hook

You already know the word pedestrian. But did you know that the word expedient — meaning a convenient solution — literally means "freeing the foot from a trap"? Or that an impediment is something that "puts a chain on your foot"?

One Latin root, ped-, unlocks dozens of English words. This week, you'll learn how to read words you've never seen before — by understanding the parts they're made from.

Root 1 — bi / bin

bi– / bin–

Latin · meaning: two

bicycle

noun

A vehicle with two wheels.

"She rode her bicycle to school."

biped

noun

A creature that walks on two feet.

"Humans are bipeds; dogs are quadrupeds."

biannual

adjective

Happening twice a year.

"The biannual report is due in June and December."

biennial

adjective

Happening once every two years.

"The biennial festival draws crowds every other summer."

bilateral

adjective

Involving two sides or parties.

"The two countries signed a bilateral trade agreement."

bifocal

adjective

Having two focal lengths (as in lenses).

"Her bifocal glasses correct both near and far vision."

Root 2 — tri

tri–

Latin/Greek · meaning: three

tricycle

noun

A vehicle with three wheels.

tripod

noun

A three-legged stand.

"The photographer set the camera on a tripod."

trilateral

adjective

Involving three sides or parties.

triennial

adjective

Happening once every three years.

Root 3 — quad / quadr

quad– / quadr–

Latin · meaning: four

quadruped

noun

An animal that walks on four feet.

"A horse is a quadruped; a human is a biped."

quadruple

verb / adjective

To multiply by four; consisting of four parts.

quadrilateral

noun

A four-sided polygon.

"A square is a type of quadrilateral."

Root 4 — cent

cent– / centi–

Latin · meaning: hundred

century

noun

A period of one hundred years.

centennial

noun / adjective

A hundredth anniversary; happening every hundred years.

"The city celebrated its centennial with a parade."

centipede

noun

Literally "hundred-footed" — a many-legged insect.

centenarian

noun

A person who is one hundred years old or more.

"At 102, she was the oldest centenarian in the district."

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Fill-in exercises

Complete each word using the correct root

Use what you've just learned. Type the complete word in the blank. The root hint is in brackets.

1. A person who has reached the age of 100 is a c___________. [cent + suffix meaning "person of that age"]

2. An animal with four legs is a q___________. [quad + ped]

3. A lens that corrects two focal lengths is called b___________. [bi + focal]

4. An event that happens twice a year is b___________. [bi + annual]

5. A 100th anniversary celebration is called a c___________. [cent + ennial]

6. A three-legged camera stand is a t___________. [tri + pod]

Key insight: Notice how bi– always means two, tri– always three, quad– always four, and cent– always hundred — regardless of what follows. Once you know a root, you can decode dozens of words you've never seen. Try: bimonthly, triennium, quadrant, centimeter — you already know what they mean.

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Think with the words

Use each word in context

Each sentence has a blank. Decide which word from this week fits best. The first letter is given.

1. India and the US signed a b___________ agreement to reduce import duties on both sides.

2. The election is b___________ — it happens once every two years, not twice a year.

3. At 103, she was the oldest c___________ in the village — and still did yoga every morning.

4. Unlike the dog, a q___________, humans are b___________s who evolved to walk upright on two legs.

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Word recall

Definition → Word

The definition is given. Write the word. The starting letter(s) are provided as a hint.

1. A four-sided geometric figure q___________

2. Occurring once every hundred years c___________

3. Involving or agreed upon by two parties b___________

4. To multiply by four q___________

5. A person 100 years old or older c___________

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Exit Slip

5 questions. Choose the best answer for each. Your answers will be logged to the tracker.

Question 1 of 5

The word biennial describes an event that occurs —

Question 2 of 5

A quadruped is an animal that —

Question 3 of 5

India and Pakistan signed a bilateral ceasefire agreement. The word bilateral means —

Question 4 of 5

Which word means "a 100th anniversary"?

Question 5 of 5

The prefix bi– means two, and focal relates to focus. So bifocal lenses must —

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