Rich or poor， young or old， we all have problems. We should learn how to deal with our problems. Here are some ways.

    Firstly， we should learn to forget.有时我们会生朋友的气。Good friendships may be lost. Sometimes children have disagreements and decide not to talk to each other. However， this usually does not last for long. This is an important lesson for us: we can solve a problem by learning to forget.

    Secondly， we should regard problems as challenges(挑战). Many students often complain about school.他们有太多的作业要做。They think the rules are too strict. Education is an important part of our development. As young people， it is our duty to try our best to deal with each challenge with the help of our teachers. Don't worry about our problems. Let's face the challenges.

下列一组数：0.6，-4$\frac{1}{2}$，（-3）²，-5，-（-1.7）中负数有（   ）

地图不仅是学习地理的工具，而且我们生活中也经常用到地图。结合所学知识完成下列各题。