1. We do addition and subtraction in arithmetic.
    在算术里，我们作加减运算。

2. He is good at mental arithmetic.
    他擅于心算。

3. She brings me cookies, and I do her arithmetic homework for her
    她给我带来了小甜饼, 我替她算术作业."

4. Psychologist Arthur F. Kramer tested volunteers working on arithmetic problems.
    心理学家阿瑟·费·克雷默对一些正在解算术题的志愿者作过测试。

5. I do the arithmetic homework for her.
    我替她做算术课家庭作业。