Numbers & Prices — I can understand and use numbers and prices in common contexts.

Historical Context & Motivation

If you've ever traveled to a French-speaking country, one of the first things you'd need to do is understand prices, addresses, and phone numbers. The French number system is not simply a matter of translating English words into French — it carries the fingerprints of a fascinating mathematical history that blends base-10 (decimal) and base-20 (vigesimal) counting traditions. Understanding where these patterns come from makes the system far easier to remember and use in everyday contexts.

So why does French say quatre-vingts (literally "four twenties") for 80 instead of something simpler? And how do you ask for a price in a Parisian café without stumbling? These are the questions this lesson answers — giving you the tools to understand and produce French numbers and prices with confidence.

Core Principles of French Numbers

French numbers follow several core principles. Once you understand these patterns, counting in French becomes much more predictable. The system is built on a few foundational ideas that govern how numbers are formed, combined, and spoken.

Visual Map of French Numbers 0–100

The diagram below maps out the entire French number system from 0 to 100, organized into color-coded zones. Notice how the pattern changes at 60 — this is where the vigesimal (base-20) logic kicks in. The top section shows the simple decimal zone, while the lower section highlights the compound constructions that make French numbers unique.

Pay special attention to the transition at 60. While numbers 20 through 59 follow a clean decimal pattern — vingt, trente, quarante, cinquante — the system shifts after soixante. There is no unique word for 70, 80, or 90 in standard French. Instead, you build these numbers by adding onto 60 or multiplying 20. This is the single most important pattern to internalize.

How French Numbers Are Constructed

While French numbers don't involve algebraic equations in the traditional sense, they do follow arithmetic formulas that you can use to construct any number. Think of each number as having a "recipe" — once you know the ingredients, you can build any number on demand.

Expressing Prices in French

Now that you can form numbers, let's put them to use in the most common real-world context: talking about prices. In French-speaking countries, the currency is typically the euro (€) in France, Belgium, and Luxembourg, or the franc in Switzerland, while many African francophone nations use the CFA franc (a distinct currency used across much of West and Central Africa). Regardless of the currency, the structure for expressing prices follows the same pattern.

Worked Example: Reading a French Restaurant Menu

Imagine you're at a restaurant in Lyon. Your server hands you a menu. You want to order a salade niçoise (€14,50), a steak-frites (€22,80), and a crème brûlée (€8,75). Let's work through saying each price in French and then calculate the total.

Common Pitfalls & How to Avoid Them

French numbers can trip up even advanced learners. The table below summarizes the most frequent mistakes students make and the correct forms to use instead. Keeping these in mind will help you avoid errors on tests and in real conversations.

Regional Variations & Looking Ahead

Standard French (as spoken in France) isn't the only version of French number words. If you travel to Belgium, Switzerland, or parts of Canada, you'll encounter regional variations that are actually simpler than the France standard. As you continue your French studies, you'll also encounter ordinal numbers (first, second, third) and larger numbers used in contexts like years, statistics, and formal writing.

As you can see, Belgian and Swiss French use more logically transparent words — septante, huitante, nonante — that follow a strict base-10 pattern. Note that within Switzerland, the word for 80 varies by canton: huitante is used in Vaud, Valais, and Fribourg, while octante appears in other Swiss regions. In your French 1 class, you'll focus on the France standard, but knowing these variants helps you understand French as a living, diverse language. In future courses, you'll tackle ordinal numbers (premier, deuxième, troisième), numbers in dates, phone numbers, and large quantities — all building on the foundations you're learning now.

Practice Problems

Lesson Summary