Question

157×78-52×78的简便运算怎么做？

Answer 1

157×78-52×78
=78×（157-52）
=78×（100+5）
=7800+78×5
=7800+390
=8190

Answer 2

157×78-52×78
=(157-52)×78
=105×78
=(100+5)×78
=100×78+5×78
=7800+390
=8290

Answer 3

157×78-52×78
=78×（157-52）
=78×105
=78×（100+5）
=78×100+78×5
=7800+390
=8190

Answer 4

原式=(157−52)×78
=105×78
=(100+5)×78
=100×78+5×78
=7800+390
=8190