a)=33/35

b)=47/8

Bài làm

a) \(\left(\frac{1}{2}+\frac{4}{7}\right)-\left(\frac{3}{7}-\frac{3}{10}\right)\)

\(=\frac{1}{2}+\frac{4}{7}-\frac{3}{7}+\frac{3}{10}\)

\(=\frac{35}{70}+\frac{40}{70}-\frac{30}{70}+\frac{21}{70}\)

\(=\frac{66}{70}\)

\(=\frac{33}{35}\)

b) \(\left(\frac{3}{5}x\frac{4}{5}x\frac{5}{9}\right):\left(\frac{7}{9}-\frac{3}{5}\right)\)

\(=\left(\frac{1}{5}x\frac{4}{3}\right):\left(\frac{35}{45}-\frac{27}{45}\right)\)

\(=\frac{4}{15}:\frac{8}{45}\)

\(=\frac{4}{15}.\frac{45}{8}\)

\(=\frac{1}{1}.\frac{3}{2}\)

\(=\frac{3}{2}\)

a, 9/1 * 3/8 + 3/8 * 9/7

b, 4/5 * 7/10 - 1/9 * 4/5

C1:nhân chia trước cộng trừ sau

C2:a,3,8x(9,1+9,7)=3,8x18,8=?

b,b, 4/5 * 7/10 - 1/9 * 4/5=4/5x(7/10-1/9)=?

bạn có thể làm kết quả luôn được ko

A  =\(\frac{2}{5}\times\frac{4}{7}+\frac{3}{5}\times\frac{4}{7}\)  B = \(\frac{17}{13}\times\frac{12}{17}-\frac{4}{13}\times\frac{12}{17}\)   C = \(\frac{9}{14}:\frac{6}{7}+\frac{5}{14}:\frac{6}{7}\)  D =\(\frac{9}{12}:\frac{7}{9}\times\frac{12}{19}\)

=  \(\frac{4}{7}\times\left(\frac{2}{5}+\frac{3}{5}\right)\)              =\(\left(\frac{17}{13}-\frac{4}{13}\right)\times\frac{12}{17}\)                = \((\frac{9}{14}+\frac{5}{14}):\frac{6}{7}\)         = \(\frac{9}{12}\times\frac{9}{7}\times\frac{12}{19}\)

=\(\frac{4}{7}\times1\)                                     = \(1\times\frac{12}{17}\)                                       = \(1:\frac{6}{7}\)                               = \(\frac{9\times9\times12}{12\times7\times19}\)

=\(\frac{4}{7}\)                                              =  \(\frac{12}{17}\)                                                =\(\frac{7}{6}\)                                    = \(\frac{9\times9}{7\times19}=\frac{81}{133}\)

   -  

a] 4/12 ; 5/12 ; 11/2 ; 1/4

b] 1 ; 9/12; 12/5 ; 11/3

c] 8/21; 6/11;8/7

d] 2/3 ;2/7 15/2

a]1/3  5/12     11/2       1/4

b]1      3/4         12/5         33/9

c]8/21      6/11        8/7

d]2/3        2/7          15/2

A) 3\7 + 5\9 +4\7+ 4\9=(3\7+4\7) + ( 5\9 +4\9) = 7\7+9\9=63\63+63\63=126\63=42\21

b) 1\5+4\11+4\5+ 7\11=(1\5+4\5)+ (4\11+7\11)=5\5+11\11=55\55+55\55=110\55=22\11

a)6/5+9/4=69/20

b)4/3-4/7=16/21

c)5/2*7/4=35/8

d)20/9:15/27=4

ban biet lam thi giai ra cho minh di

1, =4/9 x (3/7 + 2 x 4/7) - 1/9 - 3/9

= 4/9 x 1 - 1/9 - 3/9 = 0

2, = ( 22/5 x 5/22 ) x 12

= 1 x 12 = 12

2/9+3/9+4/9+5/9+6/9+7/9

=2+3+4+5+6+7/9

=27/9

=3

1/6+4/9+5/6+11/16+5/9+5/16

=1/6+5/6+4/9+5/9+11/16+5/16

=1+1+1=3

hok tốt ~

a) = 80/91

b)= 1/9

a) = 80/91

b) = 1/9

ai tích mình mình tích lại cho!!!!