Xiaoming's mother bought a basket of eggs. Xiao Ming ate a seventh on the first day, the remaining quarter on the second day, the remaining third on the third and fourth days, and the remaining half on the fifth day, leaving three eggs. How many eggs did Xiaoming's mother buy?

Before the 5th day: 3÷( 1/2)=6.

Before the 3rd day: 6 ÷ (1-1/3-1/3) =18.

Before the next day:18 ÷ (1-1/4) = 24.

Originally: 24÷( 1- 1/7)=28.

There are some books in the bookcase. One group borrows four copies, the second group borrows three copies, the third group borrows five copies, and finally the fourth group borrows 12 copies. How many books are there in this bookcase?

34 teams * * * borrowed: (12+5)÷( 1/2)=34 copies.

234 * * * team loan: (34+3)÷( 1/2)=74 copies.

1234 * * * team loan: (74+4)÷( 1/2)= 156 copies.

Plow a field with a tractor. On the first day, a quarter of the land was cultivated, 65,438+05 hectares. The next day, the remaining two-fifths and 20 hectares of land were plowed. On the third day, the remaining three quarters and 25 hectares were plowed, leaving 15 hectares. How many hectares is this land?

Sum of remaining area on the third day: (15+25) ÷ (1-3/4) =160 hectares.

The sum of the remaining area on the second day, on the third day: (160+20) ÷ (1-2/5) = 300 hectares.

* * * of this land is: (300+15) ÷ (1-1/4) = 420 hectares.