数学本来就很难，关键还要用英语表达更难对不对？一键整理搞定加减乘除啦。
加、减、乘、除：add, subtract, multiply, divide
加法、减法、乘法、除法：addition, subtraction, multiplication, division
加号、减号、乘号、除号：plus, minus, multiplication, division
每一种运算在英语口语里怎么说出来?
加法：一加一等于二
1+1=2 One plus one equals two.
在生活中有时候只需要把数字相加而不需要像数学课这样算，可以说One and one equals two. 或者：Add one and one to make two.
减法：二减一等于一
2-1=1 Two minus one equals one
同样的，可以说 One from two equals one. 或者：Subtract two from one to get one.
乘法: 三乘以六等于十八
3×6=18 Three multiplied by six equals eighteen. 或者Three times six equals eighteen.
Three sixes are eighteen. (三六十八)
在说到体积的时候一般是用by，比如：这个小包裹的尺寸是18*18*12。The dimensions of this small parcel are eighteen by eighteen by twelve.
除法: 十二除以四等于三
12÷4=3 Twelve divided by four equals three.
也可以说Four divides twelve three times.
Note: 注意各种运算中动词的时态、名词的单复数以及名词单复数时动词也要跟着有变化。
P.S. 四则运算: Four fundamental operations
