Question

72×98 144简便运算？

Answer 1

72×98+ 144
=72x98+72x2
=72x（98+2）
=72x100
=7200

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
72×98+144
= 72×98+72×2
= 72× ( 98+2)
= 72×100
= 7200