999-9999+777-12434+837471=?

999-9999+777-12434+837471=? 比较大小:777/999、7777/99999、777+7777/9999+99999 9999+999+99+9+8 999-888+777-666+999+999×0+777-444=? 999×999+888×777+1+2+3+4+6+7+8-5-9 777/9999 7777/99999 (777+7777)/（9999+99999） 999×888+888×777+777×666=? 999+9999+9999*9999+99999/99999 (-9)+(-99)+(-999)+(-9999) 9999+999+99+9 1+5+6+9+8+777+999+555=a*b 9+99+999+9999+9999+99999=? 简便方法计算99+999+9999+9999 999×888+888×777+777×666+666×555 999*999+9999简便?急等! 9999+999+99+9 9999+999+99+9+6 巧算 简便计算：①999*999+1999 ②9999*9999+19999 简算9+99+999+9999