The combination of mismatched brackets, single brackets and repositioned left and right brackets occurs often in mathematical formulae. The following is a formula that will create an error when typed:
不同括号的组合使用以及只在一侧使用括号或将括号位置左右调换的情况会经常出现。以下是一个数学例子，虽然在数学中不能这么输入，但却可以用来说明问题：