1, the dividend is enlarged and reduced by n times, and the quotient is correspondingly enlarged and reduced by n times when the divisor is unchanged. When writing vertical division, write vertical divisor first, then write dividend and divisor on the inside and left of divisor respectively, write quotient above divisor, align with the unit of dividend, and finally write the product of quotient and divisor below divisor.
2. The divisor is enlarged and reduced by n times, the dividend is unchanged, and the quotient is correspondingly reduced and enlarged by n times. The quotient invariance property is that the dividend and divisor expand or shrink by the same multiple at the same time. Quotient invariance, and continuously removing two numbers is equal to removing the product of these two numbers. The law of multiplication and distribution means that the sum of two numbers is multiplied by a number, and they can be multiplied by this number first and then added.
Divide the three digits by the dividend to get a quotient. Multiply this quotient by the dividend and write it under the dividend. When there are multiple brackets, count the brackets first, then the brackets, then the braces, and finally the brackets. It is wrong to divide 0 by any number to get 0. It should be 0 divided by any non-zero number to get 0.
In the second unit of mathematics in the second volume of the third grade, I began to learn to multiply one digit by two digits or three digits, but such a topic is a bolt from the blue for students who are still weak in writing and can't do it at all. Then, the first task is to lay a solid foundation for multiplying three digits by one digit. After all, division is the inverse of multiplication. If you can't do it well, you can't do it well in the opposite direction.