The most important content of Unit 2 and Unit 4 in the second volume of Grade Three Mathematics is pen division.

Law of integer division:

1. One digit divided by two digits (the digits of the dividend can be divisible by the dividend). Divide the digits of dividend by one digit, write the quotient on the digits of dividend, divide the digits of dividend by one digit, and write the quotient on the digits of dividend.

2. When the division is calculated vertically, write the quotient on the divisor, except where it goes.

Divider is a decimal division rule:?

1) First look at how many decimal places the divisor has, and then move the decimal point of the divisor by a few places to the right. If it is not enough, use zero to make up the digits.

2) Then divide by the fractional division of integer divisor.

Division rule of fractions:?

1) The numerator of the dividend is multiplied by the denominator of the divisor as the numerator.

2) The denominator of the dividend is multiplied by the numerator of the divisor as the denominator. (that is, the dividend is constant, the reciprocal of multiplication and division).