Question

十二分之五乘以十三分之四加十二分之七除以四分之十三？

Answer 1

十二分之五乘以十三分之四加十二分之七除以四分之十三？
答：
5/12×4/13+7/12÷13/4
=5/12×4/13+7/12×4/13
=4/13×(5/12+7/12)
=4/13×1
=4/13

Answer 2

关键点：①除以13/4，等于乘以4/13。
②用乘法分配律，提取公因数4/13。
解：5/12×4/13+7/12÷13/4
=5/12×4/13+7/12×4/13
=4/13×(5/12+7/12)
=4/13×12/12
=4/13×1
=4/13

Answer 3

12分之5×13分之4+12分之7÷4分之13
=5/12×4/13+7/12÷13/4
=5/12×4/13+7/12×4/13
=（5/12+7/12）×4/13
=1×4/13
=4/13
=13分之4

Answer 4

（5/12）×（4/13）+（7/12）÷（3/4）＝0.417×0.308+0.583÷0.75＝0.128+0.777＝0.905

Answer 5

5/12*4/13+7/12÷13/4
=5/12*4/13+7/12*4/13
=4/13*（5/12+7/12）
=4/13*1
=4/13