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1,
a,-3/5
b,-1/2
c,19/39
d,1/4
e,-39/40
f,-59/56
2,
a,=
b,<
c,>
d,<
k cho mình nha
a; \(\dfrac{9}{4}\) - \(\dfrac{-11}{4}\)
= \(\dfrac{9}{4}\) + \(\dfrac{11}{4}\)
= \(\dfrac{20}{4}\)
= 5
b; \(\dfrac{7}{8}\) - \(\dfrac{3}{-8}\) - \(\dfrac{1}{8}\)
= \(\dfrac{7}{8}\) + \(\dfrac{3}{8}\) - \(\dfrac{1}{8}\)
= \(\dfrac{7+3-1}{8}\)
= \(\dfrac{9}{8}\)
c; \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) - \(\dfrac{-1}{21}\)
= \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) + \(\dfrac{1}{21}\)
= \(\dfrac{-5-25+1}{21}\)
= \(\dfrac{-29}{21}\)
Bài 1: Ta chỉ cần bỏ ngoặc rồi cộng hai phân số để ra kết quả là số tự nhiên là xong
Bài 2:
A = \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+............+\frac{1}{2003.2004}\)
A = \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-.............-\frac{1}{2003}+\frac{1}{2003}-\frac{1}{2004}\)
A = \(1-\frac{1}{2004}\)
A = \(\frac{2004}{2004}-\frac{1}{2004}=\frac{2003}{2004}\)
Mk làm mẫu 1 bài nha
Bài 1 :
a, = (1/4+3/4) - (5/13+8/13)+2/11
= 1 - 1 + 2/11
= 2/11
Tk mk nha
BÀI 1
a, \(5\times\frac{-7}{10}=\frac{-35}{10}=\frac{-7}{2}\)
b, \(\frac{4}{5}\times\frac{-7}{10}=\frac{-28}{50}=\frac{-14}{25}\)
c, \(\frac{4}{9}+\frac{4}{3}\times\frac{16}{4}=\frac{4}{9}+\frac{16}{3}=\frac{52}{9}\)
d, \(\frac{11}{22}-\frac{3}{9}\times\frac{14}{21}=\frac{11}{22}-\frac{2}{9}=\frac{55}{198}=\frac{5}{18}\)
BÀI 2
\(A=\frac{6}{13}\times\frac{5}{7}+\frac{6}{13}\times\frac{2}{7}+\frac{17}{13}\)
\(A=\frac{30}{91}+\frac{12}{91}+\frac{17}{13}\)
\(A=\frac{30}{91}+\frac{12}{91}+\frac{119}{91}\)
\(A=\frac{161}{91}=\frac{23}{13}\)
\(B=\frac{11}{15}\times\frac{4}{11}+\frac{11}{15}\times\frac{5}{11}+\frac{11}{15}\times\frac{2}{11}\)
\(B=\frac{4}{15}+\frac{1}{3}+\frac{2}{15}\)
\(B=\frac{11}{15}\)
\(C=\left(\frac{19}{64}-\frac{33}{22}+\frac{24}{51}\right)\times\left(\frac{1}{5}-\frac{1}{15}-\frac{2}{15}\right)\)
\(C=\frac{-797}{1088}\times0\)
\(C=0\)
\(D=\frac{8}{13}\times\frac{7}{12}+\frac{8}{13}\times\frac{5}{12}-\frac{1}{12}\)
\(D=\frac{14}{39}+\frac{10}{39}-\frac{1}{12}\)
\(D=\frac{83}{156}\)
bạn biết câu náy không (24 + 11) . {546 - [14 . (64 - 2^{3}3) : 2]} =
A) 7/38 x 9/11 +7/38 x 4/11 -7/38 x 2/11
=7/38.(9/11+4/11-2/11)
=7/38
B) 5/31 x 21/25 + 5/31 x -7/10 - 5/31 x 9/20
=5/31.(21/25-7/10-9/20)
=5/31.(-31/100)
=-1/20
Bài 3:
\(a.\dfrac{5}{3}+\left(7+\dfrac{-5}{3}\right)\\ =\dfrac{5}{3}+7+\dfrac{-5}{3}\\ =\left(\dfrac{5}{3}-\dfrac{5}{3}\right)+7\\ =7\\ b.\dfrac{-7}{31}+\left(\dfrac{24}{17}+\dfrac{7}{31}\right)\\ =\dfrac{-7}{31}+\dfrac{24}{17}+\dfrac{7}{31}\\ =\left(\dfrac{7}{31}-\dfrac{7}{31}\right)+\dfrac{24}{17}\\ =\dfrac{24}{17}\\ c.\dfrac{3}{7}+\left(\dfrac{-1}{5}+\dfrac{-3}{7}\right)\\ =\dfrac{3}{7}+\dfrac{-1}{5}+\dfrac{-3}{7}\\ =\left(\dfrac{3}{7}-\dfrac{3}{7}\right)+\dfrac{-1}{5}\\ =-\dfrac{1}{5}\)
Bài 2:
a: \(\dfrac{2}{7}+\dfrac{3}{7}=\dfrac{2+3}{7}=\dfrac{5}{7}\)
b: \(\dfrac{3}{8}+\dfrac{5}{8}=\dfrac{3+5}{8}=\dfrac{8}{8}=1\)
c: \(\dfrac{1}{7}+\dfrac{-4}{7}=\dfrac{1-4}{7}=-\dfrac{3}{7}\)
d: \(\dfrac{7}{-25}+\dfrac{-8}{25}=\dfrac{-7}{25}+\dfrac{-8}{25}=-\dfrac{15}{25}=-\dfrac{3}{5}\)
e: \(\dfrac{6}{18}+\dfrac{-14}{21}=\dfrac{1}{3}-\dfrac{2}{3}=-\dfrac{1}{3}\)
f: \(\dfrac{6}{13}+\dfrac{-14}{39}=\dfrac{18}{39}-\dfrac{14}{39}=\dfrac{4}{39}\)
g: \(-\dfrac{3}{21}+\dfrac{6}{42}=-\dfrac{3}{21}+\dfrac{3}{21}=0\)
h: \(\dfrac{7}{21}+\dfrac{9}{-36}=\dfrac{1}{3}-\dfrac{1}{4}=\dfrac{1}{12}\)
Bài 4:
a: \(\dfrac{6}{5}+\left(3+\dfrac{-1}{5}\right)\)
\(=\dfrac{6}{5}+3-\dfrac{1}{5}\)
=1+3=4
b: \(-\dfrac{3}{5}+\left(-\dfrac{2}{5}+2\right)\)
\(=-\dfrac{3}{5}-\dfrac{2}{5}+2=2-1=1\)
c: \(-\dfrac{3}{5}+\left(-\dfrac{2}{5}+2\right)\)
\(=-\dfrac{3}{5}-\dfrac{2}{5}+2\)
=2-1=1
d: \(-\dfrac{5}{11}+\left(-\dfrac{6}{11}+1\right)\)
\(=-\dfrac{5}{11}-\dfrac{6}{11}+1=1-1=0\)
e: \(-\dfrac{17}{13}+\left(\dfrac{25}{101}+\dfrac{4}{13}\right)\)
\(=-\dfrac{17}{13}+\dfrac{4}{13}+\dfrac{25}{101}\)
\(=-1+\dfrac{25}{101}=-\dfrac{76}{101}\)