"字符6减字符0等于多少"...字符6减字符0等于多少
"字符1减字符0"...字符1减字符0
"字符2减字符0"...字符2减字符0
"字符9减字符0"...字符9减字符0
"字符2减字符1"...字符2减字符1
"字符3减字符2"...字符3减字符2
"字符减去字符0"...字符减去字符0
"字符减48"...字符减48
"字符减去'0'"...字符减去'0'
"字符减数字"...字符减数字
