The teaching content of the whole unit is based on pen calculation. One is to teach the vertical division and the check calculation of division through relatively easy division (there is no remainder when the number on the divisor is divided by the divisor); Then divide the number on the tens of digits by the divisor and there is a remainder; Finally, the unit of teaching quotient is the division of 0. Teaching materials reasonably insert oral calculation, estimation and solving practical problems into "want to do" or exercises.

In the third grade math book, three digits divided by one digit is divided by a pen.