Mother bought me two toy balls.
US$ per 4 yuan.
Bought me another toy car.
12 yuan
Mother gave it to cashier 50 yuan.
How much should I get back?
50-(2×4+ 12)=30
Is this ok?
The second stage has contact support.
If you think the calculation in brackets is a little difficult
You can make it easier.
Xiaoming has four boxes of books.
5 copies per box
Lend Xiaohong 9 books.
How many books does Xiao Ming have after lending?
4×5-9= 1 1