1)-73

2)-5

3)-64

4)-56

5)9

6)-20

7)6

8)-2

Tick nha

mk ra kết quả thôi nha

đăng tùng câu  một thui bạn 

bạn làm thế chắc tụi mk xỉu gần hết 

-3/8+12/25+5/-8+2/-5+13/25

=(3/8+5/-8)+12/25+2/-5+13/25

=-1+12/25+2/-5+13/25

=-13/25+2/-5+13/25

=-23/25+13/25

=-2/5

\(\dfrac{-3}{8}+\dfrac{12}{25}+\dfrac{5}{-8}+\dfrac{2}{-5}+\dfrac{13}{25}\)

\(=\dfrac{-3}{8}+\dfrac{12}{25}+\dfrac{-5}{8}+\dfrac{-2}{5}+\dfrac{12}{25}\)

\(=\left(\dfrac{-3}{8}+\dfrac{-5}{8}\right)+\left(\dfrac{12}{25}+\dfrac{12}{25}+-\dfrac{2}{5}\right)\)

Còn lại bn tự tính nhé!

\(\dfrac{-3}{8}\) + \(\dfrac{12}{25}\) + \(\dfrac{5}{-8}\) + \(\dfrac{2}{-5}+\dfrac{13}{25}\)

= \(\left(\dfrac{-3}{8}+\dfrac{5}{-8}\right)+\left(\dfrac{12}{25}+\dfrac{13}{25}\right)+\dfrac{2}{-5}\)

= \(\left(\dfrac{-3}{8}+\dfrac{-5}{8}\right)+1+\dfrac{-2}{5}\)

= 1 + 1 + \(\dfrac{-2}{5}\)

= \(\dfrac{8}{5}\)

Ta chuyển tất cả những ph/số có MS là số âm thành số dương.

Ta có : -3/8 + 12/25 + -5/8 + -2/5 + 13/25

= (-3/8 + -5/8) + ( 12/25 + 13/25) + -2/5

= -8/8 + 25/25 + -2/5

= -1 + 1 + -2/5

= 0 + -2/5

= -2/5

A=2/7+-3/8+11/7+1/3+1/7+5/-8

A=(2/7 + 1/7 + 11/7) + (-3/8 + 5/-8) + 1/3

A=2 + (-1) + 1/3

A=1 + 1/3

A=4/3

B=-3/8+12/25+5/-8+2/-5+13/25

B=(-3/8 + 5/-8) + (12/25 + 13/25) + 2/-5

B=-1 + 1 + 2/-5

B=-2/5

\(A=\left(\dfrac{2}{7}+\dfrac{11}{7}+\dfrac{1}{7}\right)+\left(\dfrac{-3}{8}+\dfrac{-5}{8}\right)+\dfrac{1}{3}=2-1+\dfrac{1}{3}=1+\dfrac{1}{3}=\dfrac{4}{3}\)

\(B=\dfrac{-3}{8}+\dfrac{12}{25}+\dfrac{-5}{8}+\dfrac{-2}{5}+\dfrac{13}{25}=1+1-\dfrac{5}{8}=-\dfrac{5}{8}\)

A=2/7+-3/8+11/7+1/3+1/7+5/-8

=(2/7+11/7+1/7)+(-3/8-5/8)+1/3

=2+(-1)+1/3 =1+1/3 =4/3

B=-3/8+12/25+5/-8+2/-5+13/25

=(-3/8-5/8)+(12/25+13/25)-5/8

=-1+1-5/8= -5/8

\(A=\frac{2}{7}+\left(-\frac{3}{8}\right)+\frac{11}{7}+\frac{1}{3}+\frac{1}{7}+\left(-\frac{5}{8}\right)\)

\(=\left(\frac{2}{7}+\frac{11}{7}+\frac{1}{7}\right)+\left(-\frac{3}{8}-\frac{5}{8}\right)+\frac{1}{3}\)

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

\(=1+\frac{1}{3}\)

\(=\frac{4}{3}\)

\(B=-\frac{3}{17}+\left(\frac{2}{3}+\frac{3}{17}\right)\)

\(=-\frac{3}{17}+\frac{2}{3}+\frac{3}{17}\)

\(=\left(-\frac{3}{17}+\frac{3}{17}\right)+\frac{2}{3}\)

\(=0+\frac{2}{3}\)

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

\(C=\frac{3}{8}+\frac{12}{25}+\frac{5}{-8}+\frac{2}{-5}+\frac{13}{25}\)

\(=\left(\frac{3}{8}-\frac{5}{8}\right)+\left(\frac{12}{25}+\frac{13}{25}\right)-\frac{2}{5}\)

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

\(=\frac{1}{12}\)

Đ/s : 2/3 nha bn

k cho mình nhé binn2011

\(-\dfrac{3}{16}+-\dfrac{3}{8}-\dfrac{5}{4}\)

\(=-\dfrac{3}{16}-\dfrac{3}{8}-\dfrac{5}{4}\)

\(=-\dfrac{3}{16}-\dfrac{6}{16}-\dfrac{20}{16}\)

\(=\dfrac{-3-6-20}{16}\)

\(=-\dfrac{29}{16}\)

\(\left(-\dfrac{25}{13}\right)+\dfrac{-9}{17}+\dfrac{12}{13}+\dfrac{25}{17}\)

\(=\left[\left(-\dfrac{25}{13}\right)+\dfrac{12}{13}\right]+\left[\left(-\dfrac{9}{17}+\dfrac{25}{17}\right)\right]\)

\(=-\dfrac{13}{13}+\dfrac{17}{17}\)

\(=-1+1\)

\(=0\)

giúp với

a) Ta có: \(A=\dfrac{2}{7}+\dfrac{-3}{8}+\dfrac{11}{7}+\dfrac{1}{3}+\dfrac{1}{7}+\dfrac{5}{-8}\)

\(=\left(\dfrac{2}{7}+\dfrac{11}{7}+\dfrac{1}{7}\right)+\left(\dfrac{-3}{8}+\dfrac{-5}{8}\right)+\dfrac{1}{3}\)

\(=2-1+\dfrac{1}{3}\)

\(=1+\dfrac{1}{3}=\dfrac{4}{3}\)

b) Ta có: \(B=\dfrac{-3}{8}+\dfrac{12}{25}+\dfrac{5}{-8}+\dfrac{2}{-5}+\dfrac{13}{25}\)

\(=\left(\dfrac{-3}{8}+\dfrac{-5}{8}\right)+\left(\dfrac{12}{25}+\dfrac{13}{25}\right)+\dfrac{-2}{5}\)

\(=-1+1+\dfrac{-2}{5}\)

\(=-\dfrac{2}{5}\)

Giải:

A= 2/7+ -3/8 +11/7 +1/3 + 1/7 + 5/-8

A= (2/7+11/7+1/7)+(-3/8+-5/8)+1/3

A= 2+ (-1) + 1/3

A= 1+1/3

A= 4/3

B= -3/8 + 12/25 + 5/-8 + 2/-5 + 13/25

B= (-3/8+-5/8) + (12/25+13/25) + -2/5

B= -1 + 1 + -2/5

B=-2/5

Chúc bạn học tốt!

a) Ta có: =(2/7+11/7+1/7)+(−3/8+−5/8)+1/3

=1+1/3=4/3

b) Ta có: =(−3/8+−5/8)+(12/25+13/25)+−2/5

=−2/5