Maths sentences: 足す and 掛ける

Question

I noticed a lack of case marking particles in mathematical sentences:

• １足す２は３である。
• ３掛ける４は１２である。

足す and 掛ける are verbs, does subject and object analysis apply to this? Do they take on the numbers as arguments despite not being marked by case particles? What part of speech are 足す and 掛ける? They do not seem to be syntactically acting as verbs.

Compare this with the English version:

• 1 plus 2 is 3
• 3 times 4 is 12

After a cursory dictionary search, it is revealed that plus and times are not verbs, but prepositions. "plus 2" and "times 4" are prepositional phrases. It seems that the structure for English is 3(times 4). While the structure in Japanese appears to me as (3掛ける)4

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If we parse 3 × 4 = 12 into English or Japanese, does the difference in grammatical syntax result in a different situation? Which situation comes to mind in English and in Japanese?:

a. 3 × 4 = OOOO + OOOO + OOOO
b. 3 × 4 = OOO + OOO + OOO + OOO

Answer 1

They are not grammatical phrases. We just read the symbols verbatim like:

[⁠1]{いち} [+]{たす} [⁠2]{に} [=]{は} [⁠3]{さん}

It has nothing different than saying:

[⁠1]{いち} [+]{プラス} [⁠2]{に} [=]{イコール} [⁠3]{さん}

which is also commonly heard. Though we have both [+]{たす／プラス} and [−]{ひく／マイナス}, [×]{かける} and [÷]{わる} only have native pronunciations.

See this link for common readings of more advanced expressions including a [>]{だいなり} b and A [⊇]{ふくむ} B, which would be aはbより大きい and AはBを含む if read grammatically.

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If we parse 3 × 4 = 12 into English or Japanese, does the difference in grammatical syntax result in a different situation? Which situation comes to mind in English and in Japanese?

It reminds me of "order of multiplication" controversy that was in Japan a while ago, but anyway, according to Japanese official teaching guidelines, multiplicand comes first and multiplier second, which results in:

b. 3 × 4 = OOO + OOO + OOO + OOO

But I'm not sure if this is grammatically elicited, because even when you say 3に4を掛ける or 3を4に掛ける in natural word order, neither of them has such implication, unless you read it 3を4回掛ける.