Party Supplies and Counter Choice
Mei is in charge of buying supplies for her Japanese class party. There are 12 students, and each student will get one bottle of juice and one cake. The shop sells juice bottles for 100 yen each, small cakes for 120 yen each, and paper plates for 20 yen each. Mei has 3,000 yen. On the order form she must write each quantity in Japanese with the correct counter: juice bottles use ほん, cakes use こ, and plates use まい. A classmate has already written a draft: 「ジュースを 12こ、ケーキを 12ほん、さらを 12まい」. Mei is not sure this draft is right, and she also needs to know whether 3,000 yen is enough for everything, including the plates.
1. Correct the classmate's draft. For each of the three items, state whether the counter is right or wrong, give the correct written form, and justify it by the item's shape.
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Corrected draft: 「ジュースを 12ほん、ケーキを 12こ、さらを 12まい」.
Reasoning: counters classify by shape, not by price or size alone. Bottles are long and thin, so ほん is used; 12 is じゅうに, and 12ほん is read じゅうにほん, with no sound change at 12. Cakes are small, round, three-dimensional objects, so こ is used: 12こ. Plates are flat and thin, so まい is used: 12まい. The classmate's version is understandable but swaps the first two: 12こ treats bottles as small round objects, and 12ほん treats cakes as long objects. The plate counter was already correct.
2. Mei has 3,000 yen. Calculate the total cost and decide whether she can also buy a 150-yen pack of napkins. Show each step.
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Juice: 12 × 100 = 1,200 yen. Cakes: 12 × 120 = 1,440 yen. Plates: 12 × 20 = 240 yen. Total: 1,200 + 1,440 = 2,640, then 2,640 + 240 = 2,880 yen. Remaining: 3,000 − 2,880 = 120 yen. A 150-yen napkin pack cannot be bought, because 120 < 150; she is 30 yen short.
The judgment depends on adding all three lines before comparing with the budget. Comparing only juice and cakes leaves 360 yen and would wrongly make the napkins look affordable.
3. A friend says 「ジュースを 12こ」 is 'grammatically wrong'. Is it a grammar error or a meaning/collocation error? Explain the difference in a way that helps Mei choose counters in an exam.
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It is not a grammar error in the strict sense. The sentence pattern 「～を 12こ」 is well formed, and a listener can understand it. The problem is semantic: こ classifies small, round objects, so it clashes with the shape of a bottle. Japanese speakers would notice the mismatch and may picture small round items.
For exam purposes, this matters because N5 counter questions test natural classification, not just whether a sentence is parseable. Mei should first identify the object's shape: long and thin → ほん; flat → まい; small and round → こ; books → さつ. Then she should check sound changes such as 1ぽん, 3ぼん, and 6ろっぽん.