bài 1 thực hiện phép tính, tính nhanh nếu có thể
a, \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
b,\(0,75.1\frac{7}{9}-1\frac{2}{5}:\frac{-21}{20}\)
c,\(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
d,\(11\frac{1}{4}-\left(2\frac{5}{7}+5\frac{1}{4}\right)\)
e,\(\left(6-2\frac{4}{5}\right).3\frac{1}{8}-1\frac{3}{5}:25\%\)
g,\(0,2.\frac{15}{36}-\left(\frac{2}{5}+\frac{2}{3}\right):1\frac{1}{5}\)
h,\(2\frac{1}{3}-\frac{1}{3}.\left(\frac{-3}{2}+\left(\frac{2}{3}+0,4.5\right)\right)\)
i,\(\frac{1}{3}.\frac{5}{7}-\frac{7}{27}.\frac{36}{14}\)
k,\(\left(\frac{-5}{28}+1,75+\frac{8}{35}\right):\left(-3\frac{9}{20}\right)\)
l,\(\left(20+9\frac{1}{4}\right):2\frac{1}{4}\)
m,\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{12.13}\)
n,\(\frac{5}{1.3}+\frac{5}{3.5}+\frac{5}{5.7}+...+\frac{5}{99.101}\)
đề bài : -3/7- (2/3 - 3/7 )
= -3/7 - 5/21
= -2/3
b) 2/15 : ( 1/3 . 4/5 - 1/3 . 6/5 )
= 2/15 : ( 1/3 . 4/5 + 6/5 )
=2/15 : 1/6
=4 /5
bạn nhớ cho mình nha
a, -3/7 - { 2/3 - 3/7 }
= -3/7 - 2/3 + 3/7
= -3/7 + 3/7 - 2/3
= 0 - 2/3
= -2/3
b, 2/15 : [ 1/3 . 4/5 -1/3 . 6/5 ]
= 2/15 : [ 1/3 . ( 4/5 - 6/5 )]
= 2/15 : [ 1/3 . ( -2/5 )]
= 2/15 : ( -2/15 )
= -1