口算:12分之11乘121分之24=(2/11)
0.4:3=(2:15)
简便计算:
11分之6乘8分之7-12分之5乘11分之6
=6/11x7/8-5/12x6/11
=6/11x(7/8-5/12)
=6/11x(21/24-10/24)
=6/11x11/24
=1/4
13分之1乘39乘21分之8
=1/13x39x8/21
=3x8/21
=8/7
=1又1/7
(20分之7-26分之5)乘4-9分之4
=(7/20-5/26)x4-4/9
=7/20x4-5/26x4-4/9
=7/5-10/13-4/9
=819/585-450/585-260/585
=109/585
(6分之5+8分之7)乘24
=5/6x24+7/8x24
=20+21
=41
方程:
3X+35分之13=7分之5
3X+13/35=5/7
3X=5/7-13/35
3X=25/35-13/35
3X=12/35
X=12/35*1/3
X=4/35
15X+(50-X)乘8
题写对了吗?
够详细了吗?