TSUMUGU · TBCL 3 (est.) · 語法
加減乘除
grammar point · tier 1 · the four arithmetic operations (A 加/減/乘以/除以 B 等於 C)
Says a sum aloud: first number, the operation verb (加 add / 減 subtract / 乘以 times / 除以 divided by), second number, 等於 equals, then the result.
Hook inherited from 量詞.
Says a sum aloud
框 · Frame
[num] 加 / 減 / 乘以 / 除以 [num] 等於 [result]
觸 · Trigger
You are reading a written sum out loud, or stating a calculation and its answer.
序 · The move
1Say the first number.A bare number, no measure word.
2Pick the operation verb: 加 (+), 減 (−), 乘以 (×), 除以 (÷).For × and ÷ in speech, the verb carries 以: 乘以, 除以.
3Say the second number, then 等於, then the result.等於 sits between the operation and its answer, not at the start.
例 · Examples
1三three乘以times / multiplied by二two等於equals六six。
Three times two equals six.
界 · Boundary
等於 vs 是等於 balances two computed quantities (the answer of a sum); 是 equates two named things (noun = noun). A result that was calculated takes 等於, not 是.
乘以 / 除以 vs 乘 / 減乘 and 除 take 以 when read as a sum (乘以、除以); 加 and 減 never do. The 以 marks 'by': times-by, divided-by.
三加二是五 → 三加二等於五 (a computed result balances with 等於, not 是)
三乘二等於六 → 三乘以二等於六 (the spoken sum puts 以 after 乘)
八除四等於二 → 八除以四等於二 (除 takes 以 in the spoken sum; 八 is the one being divided)
English 'three times two' has no spoken 'by', so learners drop the 以 and say 三乘二; and English 'equals'/'is' both map onto 等於, tempting 是 for a result.