‎30÷2(2+3)÷5= ?? 來看看專業的說法吧

http://www.neowin.net/forum/topic/989012-solve-48%C3%B7293/page__st__165


48/2(9+3) | Distributive multiplication implied by multiplication by juxtaposition
48/(2·9 + 2·3) | Evaluate brackets
48/24 | Division
2

48/2*1(9+3) | Distributive multiplication implied by multiplication by juxtaposition
48/2*(1*9 + 1*3) | Evaluate brackets
48/2*12 | Division and multiplication. LTR
24*12
288


�面有人回答,美國數學會的convetion
multiplication indicated by juxtaposition is carried out before division.
意思就是並列(省略乘號的)的乘法較除法優先


而另一方面,不採用省略乘高優先的rule,你就必須輸一堆括弧
比如說
6a ÷ 3b ÷ 2c
你必須就要寫成
6 * a ÷ (3 * b) ÷ (2 * c)
才能符合代數原意 (多麻煩?)