Adventures with the Numeral IV

Let's investigate a clever trick with the Roman numeral for four: IV! This is our first look at how ancient Romans used subtraction to write numbers in a smart and efficient way.

Getting to Know the Roman Numeral IV:
The Roman numeral 'IV' is a very clever and important symbol! Instead of writing four 'I's (IIII), the ancient Romans used a smart trick. They put an 'I' (one) *before* a 'V' (five). This is a secret code that means 'one less than five'. This is our first introduction to the subtractive principle in Roman numerals, and it's a key to understanding how bigger numbers are written. It shows that sometimes, the order of the symbols changes everything! It's a wonderful puzzle that helps us think flexibly about numbers.
- The Whizki Learning Team

Seeing the Roman Numeral IV in Our World

The Roman numeral 'IV' is a symbol for 'four' or 'fourth'. Representing it in different ways helps your child understand the clever 'one less than five' rule. Here are a few ways we can show what 'IV' really means.

The Roman Numeral

A stylized illustration of the number four, formed by connected dots and lines like a constellation.

This is the symbol 'IV'. An 'I' before a 'V' means 'one less than five'.

The Arabic Numeral

4four [fɔːr]

The Roman numeral 'IV' is equal to the number '4' that we use every day.

On a Clock

On many clock faces with Roman numerals, 'IV' marks the four o'clock position.

In a Book

The fourth chapter of a book is often labeled 'Chapter IV'. This is where the plot often gets very exciting!

Practice the Roman Numeral IV at Home (No Screens Needed!)

The best learning happens through play. Here are a few simple, screen-free ideas to continue your Roman numeral adventure together and master this clever trick.

The 'One-Less' Game

This activity is a fantastic way to understand the subtractive principle of 'IV'. You'll need five small objects, like five blocks. First, count out all five and say 'This is five, which is V'. Then, take away one block and say, 'Now we have one less than five. This is four, or IV.' This simple, physical action provides a very concrete and memorable demonstration of why IV means four. It’s a hands-on math lesson that makes an abstract rule easy to understand.

Four-Wheeled Vehicle Hunt

This is a fun scavenger hunt that connects the number four to the real world. The mission is to find as many things as you can around the house or neighborhood that have four wheels. You can find toy cars, real cars, strollers, or skateboards. For each one you find, you can write 'IV' on a piece of paper. This activity reinforces the quantity of four and helps your child see this number in the world around them, connecting the ancient numeral to modern machines.

Building with Squares

This is a great hands-on STEAM activity that connects the number four to its most stable shape: the square. You'll need craft sticks or building blocks. The challenge is to build as many perfect squares as you can. Remind your child that a square always has four equal sides and four corners. This activity is a playful introduction to geometry and reinforces one-to-one counting. It shows how the number four creates a strong and balanced foundation, which is a great metaphor for learning.

Your Guide to the Roman Numeral Code

You're currently exploring the numeral IV! Use this guide as your map to discover the other ancient symbols.
See how they are built by adding and subtracting, and jump to any other numeral you're curious about to continue your adventure.