Math常用的方法

1.Math.abs() //获取绝对值

var num = -1
     console.log(Math.abs(num)); //1

2.Math.ceil //向上取整

  var num = 5.5
        console.log(Math.ceil(num)); //6

3.Math.floor //向下取整

  var num = 5.5
       console.log(Math.floor(num)); //5

4.Math.round //四舍五入

 var num = 1.5
        console.log(Math.round(num)); //2

5.Math.max //取最大值

var arr = [1,5,2,7,6]
      console.log(Math.max(...arr));//7

6.Math.min //取最小值

  var arr = [1,2,3,5,6,2]
        console.log(Math.min(...arr)); //1

Math.random 取0-1的随机小数

 console.log(Math.random());
 //当然我们可以做一点小加工，比如和Math.round组合使用取一个0-10的整数
  console.log(Math.round(Math.random()*10));

Math.pow()获取一个值的多少次幂

 console.log(Math.pow(10，2)); //100

Math.sqrt()开方

 console.log(Math.sqrt(100)); //10