\(250\times12-\left(242+302\times2,5\right)\)

\(=3000-997\)

\(=2003\)

1/ 2016 x 7 - 7 x 2015

= 7 x (2016 - 2015)

= 7 x 1

= 7

2/ \(\frac{5}{13}\times\frac{26}{25}+\frac{3}{5}\)

\(=\frac{5\times26}{13\times25}+\frac{3}{5}\)

\(=\frac{5\times2\times13}{13\times5\times5}+\frac{3}{5}\)

\(=\frac{2}{5}+\frac{3}{5}\)

\(=1\)

Ủng hộ mk nha ^_-
 

thanks

Bn lấy câu hỏi này ở đâu ?

Biểu thức 1 :

1  4/5 x 5/6 = 9/5 x 5/6 = 45 /30 = 3/2

Biểu thức 2 : 

15/16 : 11 /4 = 15/16 x 4/11 = 15/44

Tk cho mk nha ! Kết bạn với mk nhé !

=17/6+1/2×13/3-9/4:3/5

=17/6+13/6-9/4×5/3

=17/6+13/6-15/4

=68+52-90/24

=30/24

=5/4

\(2\frac{5}{6}+0,5\times4\frac{1}{3}-2\frac{1}{4}:\frac{3}{5}\)

\(=\frac{17}{6}+\frac{1}{2}\times\frac{13}{3}-\frac{9}{4}:\frac{3}{5}\)

\(=\frac{17}{6}+\frac{13}{6}-\frac{9}{4}\times\frac{5}{3}\)

\(=5-\frac{9\times5}{4\times3}\)

\(=5-\frac{3\times5}{4\times1}\)

\(=5-\frac{15}{4}=\frac{20-15}{4}=\frac{5}{4}\)

\(\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{3}\right)x\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{5}\right)x\left(1-\frac{1}{6}\right)\)

\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.\frac{4}{5}.\frac{5}{6}\)

\(=\frac{1.2.3.4.5}{2.3.4.5.6}=\frac{1}{6}\)

Phạm Tuấn Đạt làm đúng rồi đó

Mình cũng làm theo bạn ấy

a) \(\frac{5}{12}+\frac{5}{6}-\frac{3}{4}=\frac{5}{12}+\frac{10}{12}-\frac{9}{12}=\frac{5+10-9}{12}=\frac{6}{12}=\frac{1}{2}.\)

b) \(1-\left(\frac{1}{5}+\frac{1}{2}\right)=1-\left(\frac{2}{10}+\frac{5}{10}\right)=1-\frac{7}{10}=\frac{3}{10}\)

Chúc bn học tốt !!!

1/2

3/10

3/5x(2/3-1/5:3/5)

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

=3/4x1/3=1/4

đúng 100%

\(\frac{3}{4}\cdot\left(\frac{2}{3}-\frac{1}{5}:\frac{3}{5}\right)\)

\(=\frac{3}{4}\cdot\left(\frac{2}{3}-\frac{1}{3}\right)\)

\(=\frac{3}{4}\cdot\frac{1}{3}=\frac{1}{4}\)

(3/10+4/5x1/2):1/8/9-1/1/3

=(3/10+4/10):17/9-4/3

=7/10:17/9-4/3

=63/170-4/3

=-491/510

= ( 3/10 + 2/5 ) :  17/9 - 4/3

=      7/10      :  5/9

=      63/50