For example, 42 divided by 7.

On a scale of 4 [from high to low]. When calculating the division vertically, start from most significant bit, such as: 42 from most significant bit 4; If it is not divisible, such as: 4 is not divisible by 7, then use the highest bit and the next bit to synthesize a number to be divisible until it can be divisible by the divisor; For example, if 4 is not divisible by 7 in 42, then 4 and 2 are combined into a number. If 42 is divided by 7, the quotient is 6.

Error-prone point:

When calculating the division vertically, the position of the first quotient is wrong. When the child saw that the single digit of the dividend was 0, he told the teacher that the end of division was 0, so he could ignore this principle first. The reason is that he is not familiar with vertical division and does not understand it thoroughly.

In the process of solving the problem, I didn't write down 0, thinking that 2 was the remainder. In fact, 2 corresponds to ten digits, that is, two tens, which is commonly known as 20, so I need to write down 0, change it into 20, and then calculate the division.