Numbers, Prices & Quantities — I can understand and use numbers, prices, and quantities accurately in common contexts.

Historical Context & Motivation

The French number system is one of the most fascinating artifacts of linguistic evolution in the Romance language family, reflecting centuries of contact between Latin decimal counting and Celtic vigesimal (base-20) traditions. Unlike Spanish or Italian, which adopted straightforward Latin-derived number words throughout their systems, French retained a hybrid structure that produces famously complex forms like quatre-vingts (four-twenties, i.e., 80) and quatre-vingt-dix (four-twenties-ten, i.e., 90). Understanding this historical layering helps learners predict patterns instead of relying on rote memorization alone.

The practical stakes of mastering French numbers, prices, and quantities extend well beyond academic exercises. Whether you are ordering at a Parisian boulangerie, negotiating at a Dakar market, or interpreting a receipt in Montreal, the ability to process numerical information accurately in French is essential for functional communication. Misunderstanding soixante-quinze (75) as soixante-cinq (65) can mean the difference between a correct transaction and an embarrassing error. This lesson equips you with the systematic knowledge to handle these situations across the entire Francophone world.

The central question this lesson addresses is systematic: how do the structural rules of French numeration, price expression, and quantity specification work together as a coherent grammatical subsystem, and how can a learner internalize these patterns so that numerical communication in French becomes automatic rather than labored?

Core Principles & Definitions

French numerical expression rests on several foundational principles that, once grasped, make the entire system predictable. The key insight is that French numbers follow a largely compositional logic—larger numbers are assembled from smaller building blocks according to consistent rules, with a few well-defined exceptions that learners can memorize as a finite set. Prices and quantities then layer additional grammatical considerations—gender agreement, partitive articles, and unit expressions—onto this numerical foundation.

Visual Explanation — The French Number System Map

The diagram reveals a crucial structural insight: fully two-thirds of the number system (0–69) operates on straightforward decimal logic that any Romance-language learner will find intuitive. The vigesimal zone from 70–99, while initially disorienting, involves only three additional pivot points—soixante-dix, quatre-vingts, and quatre-vingt-dix—after which the same additive unit-attachment logic applies. Learners who focus on mastering these three pivots will find the rest of the system falls into place rapidly.

How It Works — Prices, Decimals & Currency Expressions

Expressing prices in French requires combining number formation with specific conventions for currency, decimals, and oral delivery. Unlike English, which places the dollar sign before the numeral ($5.99), French places the currency symbol after the number and uses a comma as the decimal separator: 5,99 €. In speech, the structure follows the pattern: [whole number] + [currency noun] + et + [centimes/cents]. When the decimal portion is absent, centimes is simply omitted.

Price Expression Formula

Asking About Prices

Formatting Conventions

Detailed Breakdown — Quantity Expressions & Partitives

Expressing quantities in French involves a grammatical framework that integrates partitive articles, adverbs of quantity, and specific measurement units. The fundamental distinction lies between countable and uncountable nouns, just as in English, but French marks this distinction more explicitly through its article system. When expressing an unspecified quantity of an uncountable noun, French requires a partitive article (du, de la, de l'), whereas when a specific quantity expression precedes the noun, the partitive collapses to the simple preposition de (or d' before a vowel).

Common Measurement Units in Context

Worked Example — Ordering at a French Market

Imagine you are at an open-air market in Lyon. You want to buy the following items: 2 kilos of apples at 3,50 € per kilo, one bottle of olive oil at 8,95 €, and a dozen eggs at 4,20 €. The vendor speaks only French. Let us walk through the entire transaction, constructing each utterance step by step.

Regional Variations & Common Errors

One of the most practically important dimensions of French number usage is the variation across Francophone regions. While standard Metropolitan French (as taught in most textbooks) uses vigesimal forms for 70, 80, and 90, speakers in Belgium, Switzerland, and parts of West Africa often employ decimal alternatives. Awareness of these variations is essential for anyone planning to communicate across the Francophone world, and it also serves as a useful diagnostic: if you hear septante, you know you are likely interacting with a Belgian or Swiss speaker.

Frequent Errors by English Speakers

Connection to Advanced French — Ordinals, Fractions & Large Numbers

The cardinal number system you have now mastered forms the foundation for several more advanced numerical domains in French. Ordinal numbers (first, second, third...) are formed by adding the suffix -ième to the cardinal form: deux → deuxième, trois → troisième, vingt et un → vingt et unième. The sole exception is premier / première (first), which uses a suppletive form. Fractions use the ordinal as the denominator—un cinquième (one fifth)—with special forms for un demi (half), un tiers (third), and un quart (quarter).

As you advance, pay particular attention to the grammatical behavior of million and milliard (billion). Unlike mille, these are grammatical nouns: they take a plural -s (deux millions) and require de before the following noun (trois milliards d'euros). This noun-like behavior is the bridge between the number system you learned today and more complex quantitative expression in formal French.

Practice Problems

Lesson Summary