1. Xiaohong and Xiaoming go to the store to buy balloons. Xiaohong bought four red balloons, and Xiaoming and Xiaohong bought as many yellow balloons. How many balloons did they buy?

The teacher has 9 Chinese books and bought 8 more. How many Chinese books does the teacher have?

There are four birds in the tree, and five others are flying. Ask how many birds are in the tree now.

There are five red flowers and four yellow flowers on the grass, and there are as many blue flowers as yellow ones. How many blue flowers and yellow flowers are there?

There are four pears and three apples at home, and my mother bought five more apples. How many apples are there at home?