js怎值加减

// 加法示例
let a = 10;
let b = 5;
let sum = a + b; // sum 现在是 15

console.log(sum); // 输出: 15

// 减法示例
let c = 20;
let d = 7;
let difference = c - d; // difference 现在是 13

console.log(difference); // 输出: 13

let num = 5;
let str = "10";
let result = num + str; // 结果是 "510"，因为字符串被直接连接

console.log(result); // 输出: "510"

let result2 = num - str; // 结果是 -5，因为字符串被转换为数字 10 然后进行减法运算
console.log(result2); // 输出: -5

let x = 0.1;
let y = 0.2;
let z = x + y; // 结果可能是 0.30000000000000004 而不是 0.3

console.log(z.toFixed(1)); // 输出: "0.3"

let value1 = "abc";
let value2 = 5;

if (!isNaN(value1) && !isNaN(value2)) {
    let result = value1 + value2;
    console.log(result);
} else {
    console.log("输入包含非数字类型");
}