如何使用 IF 函数编写步进函数

我有 3 个数字范围，答案取决于范围。

75-79 -> 0.255
80-84 -> 0.327
85+   -> 0.559

我尝试创建一个方程，通过使用嵌套来解释范围IF函数，但 Excel 指出我为此函数输入了太多参数。下面是我输入的方程式，但它不起作用。 （X2包含数字）

=IF(X2=75,X2<=79,0.255,IF(X2=80,X2<=84,0.327,IF(X2>=85,0.559,0)))

我还尝试将数字范围输入到另一张纸中 -Age，并得到一个错误#Value!.

=IF(X2=Age!A1:A5,0.257,IF(X2=Age!A6:A10,0.327,IF(X2=Age!A11:A33,0.559,0)))

=IF(X2>=85,0.559,IF(X2>=80,0.327,IF(X2>=75,0.255,-1)))

解释：

=IF(X2>=85,                  'If the value is in the highest bracket
      0.559,                 'Use the appropriate number
      IF(X2>=80,             'Otherwise, if the number is in the next highest bracket
           0.327,            'Use the appropriate number
           IF(X2>=75,        'Otherwise, if the number is in the next highest bracket
              0.255,         'Use the appropriate number
              -1             'Otherwise, we're not in any of the ranges (Error)
             )
        )
   )