a) 7/11+3/4+4/11+1/4

=(7/11+4/11)+(3/4+1/4)

=     1           +    1

=          2.

b) 72/99-28/99-14/99

=72/99-(28/99+14/99)

=72/99-      42/99

=     30/99=10/33.

c) 69,78+35,97+30,22

=(69,78+30,22)+35,97

=      100          +35,97

=                 135,97.

d) 83,45-30,98-42,47

=83,45-(30,98+42,47)

=83,45-      73,45

=        10.

a) 2

b) 10/33

c) 135,97

d) 10

a: (7/11+4/11)+(3/4+1/4)

=11/11+4/4

=1+1=2

b: 72/99-28/99-14/99

=72/99-(28/99+14/99)

=72/99-42/99

=30/99

=10/33

c: 69,78+35,97+30,22

=(69,78+30,22)+35,97

=100+35,97

=135,97

d :83,45-(30,98+42,47)

=83,45-73,45

=10

a, = (7/11+4/11)+(3/4+1/4)

    =1+1

    =2

b,=72/99-(28/99+14/99)

=72/99-42/99

=30/99

=10/33

c,=83,45-(30,98+42,47)

=83,45-73,45

=10

thanks bn nhoa !!

1 Tính
7/12 - 2/7 + 1/12= (7/12-1/12)+2/7=6/12+2/7=1/2+2/7=7/14+4/14=11/14
12/17-5/17-4/17= 12-5-4/17=3/17

2a, 7/11+3/4+4/11+1/4= (7/11+4/11)+3/4+1/4=11/11+4/4=1+1=2
b)72/99-28/99-14/99= (72-28-14)/99=30/99=10/33

c)69,78+35,97+30,22= (69,78+30,22)+35,97=100+35,97=135,97

d) 83,45-30,98-42,47=83,45-(30,98+42,47)=83,45-73,45=10     

7/11+3/4+4/11+1/4=(7/11+4/11)+(3/4+1/4)=1+1=2

\(\frac{7}{11}+\frac{3}{4}+\frac{4}{11}+\frac{1}{4}\)

\(=\left(\frac{7}{11}+\frac{4}{11}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)\)

= 1 + 1

= 2

\(\frac{72}{99}-\frac{28}{99}-\frac{14}{99}\)

\(=\frac{72}{99}-\left(\frac{28}{99}+\frac{14}{99}\right)\)

\(=\frac{72}{99}-\frac{42}{99}\)

\(=\frac{30}{99}=\frac{10}{33}\)

7/11 + 3/4 + 4/11 +1/4

= ( 7/11 + 4/11 ) +  ( 3/4 + 1/4 )

= 1 + 1

= 2

72/99 - 28/99 - 14/99

= 72/99 - ( 28/99 + 14/99 )

= 72/99 - 42/99

= 50/99

69,78 + 35,97 + 30,22

= ( 69,78 + 30,22 ) + 35,97

= 100 + 35,97

= 135,97

83,45 - 30,98 - 42,47

= 83,45 - ( 30,98 + 42,47 )

= 83,45 - 73,45

= 10

\(\frac{72}{99}-\frac{28}{99}-\frac{14}{99}=\frac{72-28-14}{99}\)\(=\frac{30}{99}=\frac{10}{33}\)

\(\left(69,78+30,22\right)+35,97\)\(=100+35,97=135,97\)

\(83,45-\left(30,98+42,47\right)\)\(=83,45-73,45=10\)

72/99-28/99-14/99

=72/99-(28/99+14/99)

=72/99-42/99

=30/99=10/33

67,78+35,97+30,22

=(67,78+30,22)+35,97

=98+35,97

=133,97

83,45-30,98-42,47

=83,45-(30,98+42,47)

=83,45-73,45

=10

mình kick cho bạn, bạn kick cho mình

A) 72/99 - 28/99 - 14/99

= 8/11 - 28/99 - 14/99

= 8/11 - (28/99 - 14/99)

= 8/11 - 14/99

=58/99

B) 83,45 - 30,98 - 42,47 

= 8345/100 - 3098/100 - 4247/100

= 1669/20 - 1549/50 - 4247/100

= (1669/20 - 1549/50) - 4247/100

= 5247/100 - 4247/100

= 10

Tick mình nha 

A) 72/99-28/99-14/99                               B)83,45-30,98-42,47

=72/99-(28/99+14/99)                               =83,45-(30,98+42,47)

=72/99-42/99                                              =83,45-73,45

=30/99=10/33                                             =10

Bạn Nguyễn Lê Mai Thảo giải sai rồi! Sai chỗ: 8/11-(28/99+14/99) chứ không phải như bạn làm đâu!

a ) \(\frac{7}{11}+\frac{3}{4}+\frac{4}{11}+\frac{1}{4}\)

\(=\left(\frac{7}{11}+\frac{4}{11}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)\)

\(=\frac{11}{11}+\frac{4}{4}\)

\(=1+1\)

\(=2\)

b )  \(\frac{72}{99}-\frac{28}{99}-\frac{14}{99}\)

\(=\frac{72}{99}-\left(\frac{28}{99}+\frac{14}{99}\right)\)

\(=\frac{72}{99}-\frac{42}{99}\)

\(=\frac{30}{99}\)

c )  \(69,78+35,97+30,22\)

\(=\left(69,78+30,22\right)+35,97\)

\(=100+35,97\)

\(=135,97\)

d )  \(83,45-30,98-42,47\)

\(=83,45-\left(30,98+42,47\right)\)

\(=83,45-73,45\)

\(=10\)

Chúc bạn học tốt !!! 

a) 7/11 + 3/4 + 4/11 + 1/4

= ( 7/11 + 4/11 ) + ( 3/4 + 1/4 )

= 1 + 1

= 2

b) 72/99 - 28/99 - 14/99

= 72/99 - ( 28/99 + 14/99 )

= 72/99 - 42/99

= 30/99 = 10/33

c) 69,78 + 35,97 + 30,22

= ( 69,78 + 30,22 ) + 35,97

= 100 + 35,97

= 135,97

d) 83,45 - 30,98 - 42,47

= 83,45 - ( 30,98 + 42,47 )

= 83,45 - 73,45

= 10