(+2/7)+(-4/9)-(+5/9)-(-5/7)-(+1)
(+2/7)+(-4/9)-(+5/9)-(-5/7)-(+1)
答案是-1，你是要简化过程？
2/7+(-4/9)-(5/9)-(-5/7)-(+1)
(2/7+5/7)-(4/9+5/9)-1
1-1-1
-1
还有个自己动动脑筋啊，差不多也不难呀~
(4/7 * 1 1/9 * 4/11)除以(2/11 * 2/7 * 5/9) 巧算
=(4/7*10/9*4/11)/(2/11*2/7*5/9)
=(4/7÷2/7)*(10/9÷5/9)*(4/11÷2/11)
=2*2*2
=8
-2/5，3/7，-4/9，5/11，（ ）1/2
-2/5，3/7，-4/9，5/11，（-6/13 ）1/2
分子：-2,3，-4,5，-6，7
分母：5、7、9、11、13
2-6/13-9/26-2/3 5/7+5/7*4/9+13/9*2/7
2-6/13-9/26-2/3
=(2-2/3)-(6/13+9/26)
=4/3-(12/26+9/26)
=4/3-21/26=104/78-63/78=41/78
5/7+5/7*4/9+13/9*2/7
=5/7*(1+4/9)+13/9*2/7
=5/7*13/9+13/9*2/7
=13/9*(5/7+2/7)=13/9*1=13/9
算一算 1/5+2/9÷5/9= 4/15*5/6*5/12= 4÷2/3÷9/20=
1/5+2/9÷5/9
=1/5+(2/9)*(9/5)
=1/5+2/5
=3/5
4/15*5/6*5/12
=(4/15)*(5/6)*(5/12)
=(2/9)*(5/12)
=5/54
4÷2/3÷9/20
=4*(3/2)*(20/9)
=40/3
(9 2/7+7 2/9)/(5/7+5/9)=?
13
(9 2/7+7 2/9)/(5/7+5/9)=【9+7+（2/7+2/9）】)/(5/7+5/9)=【（7+9）+2（1/7+1/9）】/5（1/7+1/9）=【（7+9）/（1/7+1/9)+2】/5=(7x9+2)/5=65/5=13
[ ]*4/7=9*[ ]=[ ]*5/7=0.5*[ ]=1
[7／4]×4／7＝9×[1／9]＝[7／5]×5／7＝0.5×[2]＝1。
7÷7/9-7/9÷7=? 4/5*5/4
1题.5/6+1/2+2/3
=5/6+4/6+1/2
=3/2+1/2
=2
2题.9/20+1/3+11/20
=9/20+11/20+1/3
=1+1/3
=1又1/3
3题.2/5+1/8+7/8
=2/5+1
=1又2/5
4题.17/12-3/4-1/3
=2/3-1/3
=1/3
5题.1-2/9-7/9
=7/9-7/9
=0
6题.2/7+5/6-1/2
=2/7+1/3
=13/21
7题.4/5-1/6+1/2
=24/30-5/30+15/30
=17/15
=1又2/15
8题8/9+4/5-8/9
=8/9-8/9+4/5
=4/5
9题.1/6+3/4+1/3
=1/2+3/4
=1又1/4
6.8×16.8+19.3×3.2，139×137/138+137×1/138，4/7×1又1/9×4/11）+（2/11×2/7×5/9）
第一题：
6.8×16.8+19.3×3.2
=(10-3.2)*16.8+19.3*3.2
=168+2.5*3.2
=168+8
=176
第二题：
139*137/138+137*1/138
=[138+1]*137/138+[138-1]*1/138
=138*137/138+137/138+138*1/138-1/138
=137+137/138+1-1/138
=138+136/138
=138又68/69
第三题：
你“（ ”在那里？我看不懂
(-5/21)×2/9-7/9×5/21-5/3×1/7 怎样算?
等于（-5*2-7*5-5*3*1*3）/ (21*9) = -10/21
