Learn on PengiVocabulary from Classical Roots (Book A)Chapter 1: Numbers (Lesson 1-2)

Lesson 2: Numbers

In this Grade 4 lesson from Vocabulary from Classical Roots Book A, students learn number-based Latin and Greek roots including tri-, quad-/quart-, and dec- to unlock the meanings of words like trilogy, triumvirate, quadrant, quatrain, and decathlon. The lesson connects each root to its numeric value through real-world and literary examples, building vocabulary within the context of classical language study. Students also explore related roots for numbers five through nine, broadening their understanding of how ancient languages shape modern English.

Section 1

Three's Company

Key Words

Let's explore words that all share the root TRI, meaning "three."

trilogy (n.)trisect (v.)triumvirate (n.)

Example Usage

📝Example Usage:

  • The principal, vice-principal, and dean of students formed a triumvirate to make important decisions for the school.
  • To share the pizza fairly among the three friends, they had to trisect it carefully.
  • J.R.R. Tolkien's The Lord of the Rings is a famous trilogy that tells one epic story across three books.

Section 2

The Power of Four

Key Words

Now for words from the roots QUARTUS and QUATUOR, both meaning "four."

quadrant (n.)quartet (n.)quatrain (n.)

Example Usage

📝Example Usage:

  • A classic barbershop quartet features four voices singing in close harmony.
  • The poem was composed of a single quatrain, with four lines that rhymed perfectly.
  • Ancient astronomers used an instrument called a quadrant to measure the altitude of stars.

Section 3

A Perfect Ten

Key Words

These next words come from the root DECEM, which means "ten."

decimate (v.)decathlon (n.)

Example Usage

📝Example Usage:

  • The Olympic decathlon is a grueling two-day competition that tests athletes in ten different track and field events.
  • An invasive insect infestation can decimate a farmer's entire crop if not handled quickly.

Section 4

Counting to a Hundred

Key Words

Finally, let's look at words derived from CENTUM, the Latin word for "hundred." These words help us measure time, temperature, and quantity in units of 100.

bicentennial (n.)centenary (adj.)centigrade (adj.)

Example Usage

📝Example Usage:

  • The United States celebrated its bicentennial in 1976, marking 200 years since the Declaration of Independence was signed.
  • In many parts of the world, temperature is measured on the centigrade scale, where water freezes at 0 degrees.
  • A centenary celebration marks the 100th anniversary of a significant event.

Book overview

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Chapter 1: Numbers (Lesson 1-2)

  1. Lesson 1

    Lesson 1: Numbers

  2. Lesson 2Current

    Lesson 2: Numbers

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

Three's Company

Key Words

Let's explore words that all share the root TRI, meaning "three."

trilogy (n.)trisect (v.)triumvirate (n.)

Example Usage

📝Example Usage:

  • The principal, vice-principal, and dean of students formed a triumvirate to make important decisions for the school.
  • To share the pizza fairly among the three friends, they had to trisect it carefully.
  • J.R.R. Tolkien's The Lord of the Rings is a famous trilogy that tells one epic story across three books.

Section 2

The Power of Four

Key Words

Now for words from the roots QUARTUS and QUATUOR, both meaning "four."

quadrant (n.)quartet (n.)quatrain (n.)

Example Usage

📝Example Usage:

  • A classic barbershop quartet features four voices singing in close harmony.
  • The poem was composed of a single quatrain, with four lines that rhymed perfectly.
  • Ancient astronomers used an instrument called a quadrant to measure the altitude of stars.

Section 3

A Perfect Ten

Key Words

These next words come from the root DECEM, which means "ten."

decimate (v.)decathlon (n.)

Example Usage

📝Example Usage:

  • The Olympic decathlon is a grueling two-day competition that tests athletes in ten different track and field events.
  • An invasive insect infestation can decimate a farmer's entire crop if not handled quickly.

Section 4

Counting to a Hundred

Key Words

Finally, let's look at words derived from CENTUM, the Latin word for "hundred." These words help us measure time, temperature, and quantity in units of 100.

bicentennial (n.)centenary (adj.)centigrade (adj.)

Example Usage

📝Example Usage:

  • The United States celebrated its bicentennial in 1976, marking 200 years since the Declaration of Independence was signed.
  • In many parts of the world, temperature is measured on the centigrade scale, where water freezes at 0 degrees.
  • A centenary celebration marks the 100th anniversary of a significant event.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 1: Numbers (Lesson 1-2)

  1. Lesson 1

    Lesson 1: Numbers

  2. Lesson 2Current

    Lesson 2: Numbers