加、减、乘、除及相关运算用英文怎么说？

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