Question

139x一百三十八分之一百三十七+137x一百三十八分之一= 要简便运算.求高手解答.谢~~

Answer 1

分配率运算简单
=137x137/138+2x137/138+137x1/138
=137x（137/138+1/138）+2x137/138
=137x1+2x137/138
=137+1又68/69
=138又68/69

Answer 2

解：简便运算
139X137/138+137X1/138=139X137/138+137/138=137/138X(139+1)=137/138X400=137X400/138=137X200/69=27400/69=397，7/69(397又7/69)

Answer 3

139x一百三十八分之一百三十七+137x一百三十八分之一= 要简便运算.求高手解答.谢~~
139x137/138+137x1/138
=139x137/138+137/138
=（139+1）x137/138
=140x137/138
=140x（1-1/138）
=140-70/69
=138又68/69

Answer 4

139x一百三十八分之一百三十七+137x一百三十八分之一= 简便运算如下：
139×137/138+137×1/138
=（138+1）×137/138+137/138
=138×137/138+1×137/138+137/138
=137+137/138×2
=137+1又68/69
=138又68/69
或者：
139×137/138+137×1/138
=（138+1）×137/138+（138-1）×1/138
=138×137/138+1×137/138+138×1/138-1×1/138
=137+137/138+1-1/138
=（137+1）+（137/138-1/138）
=138+68/69
=138又68/69

Answer 5

139×137/138+137×1/138，
=137×（139+1）/138，
=137×140/138，
=（138-1）×140/138，
=140-140/138，
=139-1/69，
=138又68/69