Divider and divisor are multiplied or divided by the same number that is not 0 at the same time, and the quotient remains unchanged; If the dividend is constant, the quotient will be reduced by many times as the divisor is enlarged.

How many times the divisor is reduced, how many times the quotient is expanded; How many times the divisor is enlarged, how many times the quotient is enlarged, and how many times the dividend is reduced.

The fourth grade refers to "Help You Learn Mathematics Workbook: The Fourth Grade of Primary Mathematics/Synchronize with the Experimental Textbook of the People's Education Edition/Newly-compiled Parent Counseling Series", which is compiled according to the latest curriculum standard of primary and secondary school students of the Ministry of Education and in coordination with the Experimental Textbook of Nine-year Compulsory Education and Six-year Curriculum Standard of Primary School of the People's Education Edition.