题目内容
用字母表示运算定律和运算规律.
(a+b)×c=________×________+________×________
a+b=________ +________
a÷(b×c)=a÷________÷________
a+b+c=(___+___)+___=___+(___+___)
a-b-c=a-(________+________)
a×b=________×________