Physical education class, Class One, Grade Six, has three rows 1 person, three rows 1 person, five rows1person and five rows/person. How many students did you send to physical education class?

6 times 4 divided by 2 equals 12.

12 times 5 and subtracts 1 to get 59.

A: There are 59.

Xiaohong planted trees around the playground. At first, she planted a tree every 3 meters. After planting nine trees, she found that there were not enough saplings. So she decided to replant and plant a tree every 4 meters. How many trees will she pull up when replanting?

Plant a tree every 3 meters, arranged as follows: 0, 3, 6, 9, 12, 15, 18, 2 1 24.

Plant a tree every 4 meters, arranged as follows: 0, 4, 8, 12, 16, 20, 24, 28, 32.

You don't have to pull the same one, so there are three trees that don't have to be pulled.