Prices, Quantities & Measurements — I can talk about prices, quantities, and simple measurements using numbers and common units in familiar contexts.

Historical Context & Motivation

If you have ever tried to buy a snack at a Japanese convenience store, order food at a ramen shop, or read a recipe in Japanese, you have already encountered the need to understand prices, quantities, and measurements. Japanese handles numbers differently from English in several key ways: the currency system uses a single base unit (the yen) without smaller denominations like cents, and the language requires special counter words (助数詞 — josūshi) that must be attached to numbers whenever you count objects, people, or units of measure. Understanding these patterns is essential for real-world communication in Japan.

Today, every trip to a Japanese store, restaurant, or market requires you to understand and produce sentences about prices, count items using the correct counter word, and express measurements in metric units. The core question this lesson addresses is: How do you combine Japanese numbers with counters, currency, and measurement units to communicate clearly in everyday situations?

Core Principles & Definitions

Before diving into specific vocabulary, you need to understand the foundational ideas that govern how Japanese expresses prices, quantities, and measurements. Unlike English, where you simply say "three apples" or "five dollars," Japanese requires you to insert a counter suffix between the number and the context. Think of counters as mandatory classifiers that tell the listener what kind of thing you are counting.

Visual Explanation — Number + Counter + Context

The diagram above illustrates the fundamental building blocks of every sentence you will create in this lesson. Notice how the number and counter are fused together — they function as a single adverbial unit. In a price sentence, the counter is 円 (en). In a quantity sentence, you pick from a menu of counters based on the shape or category of the item. In a measurement sentence, you use a metric unit word. The particle before the number-counter unit changes depending on the sentence's purpose: は (wa) for "is," を (o) for objects being requested, and が (ga) for subjects. Mastering these three patterns covers the vast majority of real-life situations you will encounter.

How It Works — Number Systems & Sound Changes

The Sino-Japanese Number System (いち、に、さん…)

For prices, quantities, and measurements, you will primarily use the Sino-Japanese (on'yomi) number system. This system was borrowed from Chinese and is used with most counters and all currency expressions. The numbers from one to ten are: いち (1), に (2), さん (3), し/よん (4), ご (5), ろく (6), しち/なな (7), はち (8), きゅう/く (9), and じゅう (10). For numbers above ten, you combine these: じゅういち (11), にじゅう (20), ひゃく (100), せん (1,000), and まん (10,000). Note that Japanese groups large numbers by ten-thousands (万 — man), not by thousands like English.

Sound Change Rules (音便 — onbin)

When certain numbers combine with certain counters, the pronunciation changes to make the word easier to say. These sound changes (音便 — onbin) are not random — they follow patterns based on whether the counter starts with an h-, k-, s-, or t- sound. The most important patterns involve numbers 1, 3, 6, 8, and 10. For example, with the counter 〜本 (hon, for long objects), いち + ほん becomes いっぽん (ippon), さん + ほん becomes さんぼん (sanbon), and ろく + ほん becomes ろっぽん (roppon). Similarly, with 〜百 (hyaku, hundred), さん + ひゃく becomes さんびゃく (sanbyaku), and ろく + ひゃく becomes ろっぴゃく (roppyaku).

Essential Counters & Measurement Units

Now that you understand how numbers and counters work together, let's map out the most useful counters and units you will encounter in everyday Japanese. The following diagram organizes them by category so you can quickly identify which counter to use based on what you are talking about.

Common Counters in Detail

Worked Example — Shopping at a Convenience Store

Let's walk through a realistic conversation at a Japanese convenience store (コンビニ — konbini). You want to ask the price of onigiri, buy two of them plus a bottle of tea, and confirm the total. This example combines all three skill areas: asking about prices, specifying quantities with counters, and understanding the response.

Common Pitfalls & How to Avoid Them

Even after understanding the rules, learners frequently stumble over certain patterns. Let's look at the most common mistakes and how to fix them. Being aware of these pitfalls now will save you from confusion later.

Connection to Advanced Japanese

The counter system you've learned here is just the beginning. Japanese has over 500 counters, though only about 30 are commonly used. As you advance, you'll encounter specialized counters for animals (〜匹 hiki for small animals, 〜頭 tō for large ones), machines (〜台 dai), buildings (〜軒 ken), and even abstract concepts like occurrences (〜回 kai) and floors of a building (〜階 kai). The good news is that the sound-change patterns you've mastered now apply to almost all of them.

As you progress, you will also learn to express approximate quantities using 〜ぐらい (gurai — about) and 〜ほど (hodo — approximately), make comparisons using より (yori — than), and discuss ranges with 〜から〜まで (kara...made — from...to). All of these build directly on the number + counter foundation you are establishing now, so invest time in getting these basics solid.

Practice Problems

Test your understanding with these five problems. They progress from basic recall to more complex real-world scenarios. Try to answer each one before reading the solution.

Lesson Summary