How many digits are accurate in Sql and cut off the extra 0

SELECT  CAST(--cast是转换类型
        CONVERT(DECIMAL(18, 4)--4是保留几位
        , ROUND(CONVERT(DECIMAL(18, 4), 2000)--2000是数值
                / 10000, 4)) AS VARCHAR(20)) + '万平' AS gzssfwcc_bld_mj;