二年级括号里最大填几乘法 括号2/3-4/7括号乘21+4/5。

括号2/3-4/7括号乘21+4/5。  

括号2/3-4/7括号乘21+4/5。

括号2/3-4/7括号乘21+4/5。
=2/3×21-4/7×21+0.8
=14-12+0.8
=2+0.8
=2.8

5/13×括号6/17-3/26括号乘2/3-4/17=

5/13×括号6/17-3/26括号乘2/3-4/17=
＝5/13*6/17*2/3-5/13*3/26*2/3-4/17
＝（5*2*2）/（13*17）-5/（13*13）-4/17
＝20/221-5/169-4/17
＝（20/221-4/17）-5/169
＝（20/221-52/221）-5/169
＝-32/221-5/169
＝-32*13/（221*13）-（5*17）/（169*17）
＝-416/2873-85/2873
＝-501/2873

括号6/7乘以2/3括号乘以4/5

16/35

括号2/3 5分之3-4/9括号乘以四分之五

括号2/3 5分之3-4/9括号乘以四分之五
(2/3+ 3/5-4/9)x(5/4)
=(2/3-4/9)x(5/4)+ 3/5x(5/4)
=(6/9-4/9)x(5/4)+ 3/4
=2/9x(5/4)+ 3/4
=10/36+ 3/4
=10/36+27/36
=37/36

2/5÷中括号，括号2/3+1/5括号乘1/13括号。

2/5÷【（2/3+1/5）x1/13】
=2/5÷（13/15x1/13）
=2/5÷1/15
=6

括号-1/42÷括号-1/6-3/14+2/3-4/7

（-1/42）÷（-1/6）-3/14+2/3-4/7
=1/7-3/14+2/3-4/7
=(1/7-3/14-4/7)+2/3
=-9/14+2/3
=1/42

括号2/3-7分之3+4/9括号乘63

(2/3-3/7+4/9)×63
=2/3×63-3/7×63+4/9×63
=2×21-3×9+4×7
=42-27+28
=43

2/5÷中括号括号2/3+1/5括号乘1/13中括号

2/5÷[（2/3+1/5）x1/13]
=2/5÷（13/15x1/13）
=2/5÷1/15
=2/5x15
=6

括号二又4/7除以2又2/3乘以括号-2.8括号

（2又4/7）÷（2又2/3）x(-2.8)
=-18/7÷8/3x14/5
=-27/28x14/5
=-27/10

括号13/14×2/7括号乘21/26

括号13/14×2/7括号乘21/26
=13/14x2/7x21/26
=13/14x21/26x2/7
=3/4x2/7
=3/14