If you want to know what arithmetic means in grade one, you must first know what it means. Arithmetic is the truth in the process of calculation, the way of thinking in the process of calculation, and the problem of solving why it is calculated like this. Therefore, in the first grade, oral arithmetic is to master the truth, understand his meaning and open up his mind, so as to calculate faster, for example: 15-7=? We can teach students to think of 15 as 10+5, and then subtract 7 to get 10-7 plus 5, which is easy to solve; We can also change our thinking and make students think about 7+? = 15, thus 15-7=? Solve the problem of subtraction from the angle of addition.