bài 1: thực hiện phép tính
a. 7/4 + 9/16
b. -70/27 + 35/9
c. -4/-5 + (-2/3)
d. -19/ + 3/8 - (-4/3)
i. -7/2 + (-5/-4) - 4/-9
k. 1/4 + 1/3 - 1/2
m. -1/9 - 1/7 - 3/4
n. 11/12 - (-3/18) + 5/6
o. 20/17 + (-11/2) - 30/4
v. 1/2 - 3/4 + 5/6
e. -2/3 - 1/7 + (-6/2)
f. -4/5 + 3/10 - 2/-15
g. 20/21 + (-19/-3) - 12/7
h. 1/4 - 7/2 + 3/11
y. -9/4 - 1/7 + 12/-7
cảm ơn vì đã giúp em ạ.
a/
$\frac{7}{4}+\frac{9}{16}=\frac{28}{16}+\frac{9}{16}=\frac{28+9}{16}=\frac{37}{16}$
b/
$\frac{-70}{27}+\frac{35}{9}=\frac{-70}{27}+\frac{105}{27}=\frac{35}{27}$
c/
$\frac{-4}{-5}+\frac{-2}{3}=\frac{4}{5}-\frac{2}{3}=\frac{12}{15}-\frac{10}{15}=\frac{2}{15}$
d/ Đề thiếu. Bạn xem lại.
i/
$\frac{-7}{2}+(\frac{-5}{-4}-\frac{4}{-9}$
$=\frac{-7}{2}+\frac{5}{4}+\frac{4}{9}$
$=\frac{-14}{4}+\frac{5}{4}+\frac{4}{9}$
$=\frac{-9}{4}+\frac{4}{9}=\frac{-81}{36}+\frac{16}{36}=\frac{-65}{36}$
k/
$\frac{1}{4}+\frac{1}{3}-\frac{1}{2}$
$=\frac{3}{12}+\frac{4}{12}-\frac{6}{12}=\frac{1}{12}$
m/
$\frac{-1}{9}-\frac{1}{7}-\frac{3}{4}$
$=-(\frac{1}{9}+\frac{1}{7}+\frac{3}{4})$
$=-(\frac{28}{252}+\frac{36}{252}+\frac{189}{252})$
$=\frac{-253}{252}$
n/
$\frac{11}{12}-(\frac{-3}{18}+\frac{5}{6}$
$=\frac{11}{12}+\frac{1}{6}+\frac{5}{6}$
$=\frac{11}{12}+1=\frac{23}{12}$
o/
$\frac{20}{17}+\frac{-11}{2}-\frac{30}{4}$
$=\frac{20}{17}-\frac{11}{2}-\frac{15}{2}$
$=\frac{20}{7}-13=\frac{-71}{7}$
v/
$\frac{1}{2}-\frac{3}{4}+\frac{5}{6}$
$=\frac{6}{12}-\frac{9}{12}+\frac{10}{12}$
$=\frac{6-9+10}{12}=\frac{7}{12}$
e/
$\frac{-2}{3}-\frac{1}{7}+(\frac{-6}{2})$
$=-(\frac{2}{3}+\frac{1}{7})-3$
$=-\frac{17}{21}-3=-\frac{80}{21}$
f/
$\frac{-4}{5}+\frac{3}{10}-\frac{2}{-15}$
$=\frac{-24}{30}+\frac{9}{30}+\frac{4}{30}$
$=\frac{-11}{30}$
g/
$=\frac{20}{21}+\frac{133}{21}-\frac{36}{21}$
$=\frac{117}{21}=\frac{39}{7}$
h/
$=\frac{1}{4}-\frac{14}{4}+\frac{3}{11}$
$=\frac{-13}{4}+\frac{3}{11}=\frac{-131}{44}$
y/
$=-(\frac{9}{4}+\frac{1}{7}+\frac{12}{7})$
$=-(\frac{9}{4}+\frac{13}{7})=-\frac{115}{28}$
