Question

9X123-9×23简便计算？

Answer 1

9X123-9×23
=9x(123-23)
=9x100
=900

Answer 2

乘法分配律为：两个数的和与一个数相乘，先将它们与这个数分别相乘，再相加，积不变．即：（a+b）×c=a×c+b×c．反过来则：a×c+b×c=（a+b）×c
9×123-9×23
= 9× ( 123-23）
= 9×100
= 900