ずつ & わりで
In this lesson, we will learn about the adverbial particle ずつ, along with the similar expression ～わりで.
The Adverbial Particle ずつ
The adverbial particle ずつ1 is used to indicate groupings, and while that may seem straightforward, learners and instructors alike often find its mechanics to be somewhat confusion.
First, consider the following example sentences.
1. それでは、出発しますよ。子供１０人に、２名ずつ、お母さんがついてくださるようにご協力をお願いします！
Alrighty, it’s time to head out! We ask for your cooperation in having 2 mothers accompany every 10 children!
The visualization of this scenario is that the kids are being grouped from start to finish in groups of 10, and for each group of 10, a group made up of 2 mothers is assigned. Group A = the kids, and Group B = the mothers. We can then rationalize this as a ratio: “A:B.” So far, so good, but next, let’s assign the numbers a designation. For the number that accompanies Group A, we will refer to it as #甲, and for the number that accompanies Group B, we will refer to it as #乙.
In both English and Japanese, it is more common for one to say “give # (B) to each (A=1甲)” as opposed to “give # (B) to (A=2(+)甲).” Simply put, the most common ratios are those in which Group A = 1. In the following example, 2a demonstrates how such a ratio is expressed with ずつ, and 2b shows how one might paraphrase ずつ out while still saying essentially the same thing.
2a. カードはひとり１０枚ずつですよ。
2b. ひとりあたり１０枚になるように、カードを配ってください。
Interestingly enough, while 2a does present itself as the most succinct means of writing the ratio 1:10, similar sentences cause headaches to learners and instructors alike when [A=1] is not so blatantly apparent, which is to say, what can constitute to A is not limited to nouns or counter phrases restricted to the number 1 so long as one entity is the result. With that said, consider 3a and its paraphrasing 3b.
3a. 教科書は2冊ずつ、小説は5冊ずつ、雑誌は5冊ずつ、３本の紐で括ってください。
3b. １括りにつき、教科書が2冊、小説が5冊、雑誌が5冊になるように、3本の紐で縛ってください。
3a. Please tie together two textbooks, five novels, and five magazines with three pieces of string (in each bundle).
3b. Please tie them with three strings so that each bundle contains two textbooks, five novels, and five magazines.
From the translations, we can deduce that the A in [A=1] is a bundle. That bundle is comprised of [３本の紐], but the appearance of “3” within A does not affect how this ratio functions, nor does there being multiple components to B affect it. This can all be rationalized with some math: A[n parts]: B[n parts]. If anything, the repetition of the particle ずつ helps make it abundantly clear that the speaker is extending the range of B. The last source of confusion for a learner is that ratios are not always verbalized in the rigid order A:B like a mathematician may like. In 3a, B is stated first, and with A having a number inside it, despite still equating to 1, this does complicate the sentence as far as word order is concerned. However, ずつ ALWAYS marks the B in a ratio, so whether or not A is stated first, that fact is the one constant you should look out for.
While in many instances, B constitutes a direct object, and A constitutes an indirect object, this is not always the case. In Ex. 4, A is actually the direct object, and B is marked with the particle で to indicate means, as the allocation of B to A actually constitutes [A=1].
4a. まず８人ずつで輪をつくってください。
4b. ひとつの輪が、８人からできているように、輪をつくってください。
Oddly enough, in actual conversation, when both A and B = 1, we find that A is often emphatically repeated, as if to say the simplest ratio is likely the very ratio someone might mess up in execution.
5. この２０冊の雑誌をひとりひとりに一冊ずつ配ってください。
Please pass out to each and every person one of these twenty magazines.
There is also the issue of implied A components and how A might manifest temporally, which again, other numbers may be involved, but each interval would still constitute as 1 interval. First, consider the following.
6. 2～3日ごとに１回ずつジムに行くように努力している。
I am trying to go to the gym once every 2-3 days.
7. ３月になったら、少しずつ暖かくなっていった。
Once it was March, it started to get warmer little by little.
8. 一人ずつバスに乗りなさい。
Please enter the bus one by one.
In Ex. 6, is A is represented by [2～3日ごと], but this is a repeated interval; thus, [A=1] does not change. In Ex. 7, A is not explicitly stated, but it can be deduced from context as being [per day = 1]. Incidentally, B is not stated succinctly either. In Ex. 8, A can be understood as groups of passengers, with each group incidentally only being composed of 1 passenger.
To conclude, let’s look at a healthy sample of examples with ずつ for practice.
9. 毎日、漢字を5つずつ覚えています。
I’m learning 5 kanji at a time every day.
10. 順番に一つずつ質問してください。
Please ask questions in order, one at a time.
11. 監視護衛は、約20人が一週間ずつ交代で当たっていました。
About 20 guards were on duty, taking turns for one week at a time.
Sentence Note: The number of guards on duty on any given week is not clear from Ex. 11. The guards could be evenly split up, 10 per week, or the number of guards could be allocated differently depending on the needs on the ground. All that, though, is irrelevant to this statement. In Ex. 11, all we can deduce is that all 20 guards are being given a rotation of one week.
12. 半分ずつにして一緒に食べよう！
Let’s eat them together, each of us getting half!
13. さつまいものタルト、クリームチーズケーキ、ティラミス、モンブラン、ガナッシュケーキ、各２個ずつ１０個のセットを販売しております！
We are selling sets of 10 cakes, two of each: sweet potato sponge cake, cream cheese cake, tiramisu, Mont Blanc, and ganache cake!
14. 男女３人で、ビール４杯ずつ、焼酎２敗ずつに料理をお腹一杯食べて６０００円くらいでした。個人的にお勧めしたいお店です。
For three of us, men/women, we had four beers, two shochu drinks, and a full meal each, and it cost about 6,000 yen. I personally recommend this restaurant.
～わりで
One thing you may have noticed is that with the use of ずつ, there is an implied flow of events as the ratio is acted out. If, however, one wishes only to state a ratio/proportion, one can use ～割で・割合で instead. These alternatives tend to be preferred in mathematics, so as to avoid confusion.
15. 1時間に10マイルのわりで、いつ目的地に着きますか。
At ten miles per hour, when will you arrive at your destination?
16. 白米１２／３合（３００ｍｌ）に対して、雑穀１／３合（６０ｍｌ）の割合で合わせて混ぜる。
Mix together 12/3 go (300 ml) of white rice with 1/3 go (60 ml) of millet.
参照
『日本語類義表現使い分け辞典』by 泉原省二.
- The particle ずつ is historically written as づつ, and this traditional spelling is still occasionally used. Rarely, it may also be spelled in kanji as 宛つ. ↩︎