phép tính cứ làm bình thường nha nhân chia trước cộng trừ sau , cái gì trung đặt ra ngoài .xin lỗi vì vt hơ mỏi tay nên mik vt lời thôi nha 

~ hok tốt ~

cút m*** đi!!

a) \(30+\left(-30\right)+7\)

\(=30-30+7\)

\(=0+7\)

\(=7\)

b) \(12+\left(-31\right)\)

\(=12-31\)

\(=-31+12\)

\(=-\left(31-12\right)\)

\(=-19\)

c) \(\left(-40\right)+\left(-20\right)+\left(-40\right)\)

\(=-40-20-40\)

\(=-\left(40+20\right)-40\)

\(=-60-40\)

\(=-\left(60+40\right)\)

\(=-100\)

d) \(13+\left|-13\right|\)

\(=13+13\)

\(=26\)

e) \(\left|-13\right|+\left|-12\right|+\left|-17\right|\)

\(=13+12+17\)

\(=25+17\)

\(=42\)

f) \(-17+\left|-17\right|+12\)

\(=-17+17+12\)

\(=-\left(17-17\right)+12\)

\(=-0+12\)

\(=-\left(0-12\right)\)

\(=-\left(-12\right)\)

\(=12\)

a, = 7

b, = -19

c, = -100

d, = 26

e, = 42

f, = 12

-17.(13+5) - 13.(17-2)

=-17.13+(-17).5-13.17+13.2

=-17.13+(-17).5 + 13 . (-17) + 13.2

=-17.(13+5+13) + 13.2 

=-17. 31 +26

=-501

=181+(3-4-5+6)+(7-8-9+10)+(11-12-13+14)+(15-16-17+18)+19

=181+0+0+0+0+19

=181+19

=200

\(\frac{75}{100}+\frac{17}{20}+\frac{8}{13}+\frac{1}{4}+\frac{5}{13}+\frac{3}{20}\)

\(=\left(\frac{75}{100}+\frac{1}{4}\right)+\left(\frac{17}{20}+\frac{3}{20}\right)+\left(\frac{8}{13}+\frac{5}{13}\right)\)

\(=1+1+1\)

\(=3\)k cho mình nha

79*50 = 3950

79*50 = 3950

=(17/12+19/12)+(3/5+2/5)+(8/13+18/13)

=3+1+2

=6

\(\frac{17}{12}+\frac{3}{5}+\frac{19}{12}+\frac{8}{13}+\frac{2}{5}+\frac{18}{13}\)

\(=\left(\frac{17}{12}+\frac{19}{12}\right)+\left(\frac{8}{13}+\frac{18}{13}\right)+\left(\frac{3}{5}+\frac{2}{5}\right)\)

\(=3+2+1\)

\(=6\)