999×888+888×777+777×666=?
问题描述:
999×888+888×777+777×666=?
答
999×888+888×777+777×666
=111×9×111×8+111×8×111×7+111×7×111×6
=111×111×(9×8+8×7+7×6)
=111×111×170
=2094570