freeCodeCamp/guide/chinese/certifications/javascript-algorithms-and-data-structures/basic-javascript/compound-assignment-with-augmented-subtraction/index.md

title	localeTitle
Compound Assignment With Augmented Subtraction	具有增广减法的复合赋值

具有增广减法的复合赋值

计算机从左到右阅读。因此，使用' - ='运算符意味着变量被右侧的数字减去，然后变量被赋值给差值。像这样：

var b = 10; 
 b -= 4; // Now, 'b' is 6