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\(a)\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{2}{5}=1+\frac{2}{5}=\frac{7}{5}\)
\(b)\frac{5}{7}.\frac{2}{3}.\frac{14}{15}=\frac{5.2.14}{7.3.15}=\frac{4}{9}\)
\(c)\frac{3}{8}+\frac{2}{5}.\frac{5}{8}=\frac{3}{8}+\frac{1}{4}=\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\)
\(d)\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{7}{15}=\frac{4}{15}\)
~Học tốt~
4/5 x 15/11 x 2/9 = 8/33
4/7 x 2/5 + 4/7 x 3/5 = 4/7
( 5/7 + 7/8 ) x 2 = 89/28
2/14 + 3/7 - 3/14 x 2 = 1/7
tk mình nhé, mk nhanh nhất
a,Cách 1: (6/11 + 5/11 ) x 3/7 Cách 2 :(6/11 + 5/11) x 3/7
= 1 x 3/7 =6/11 x 3/7 + 5/11 x 3/7
= 3/7 = 18/77 + 15/77
= 3/7
b, Cách 1:3/5 x 7/9 - 3/5 x 2/9 Cách 2 :3/5 x 7/9 - 3/5 x 2/9
= 7/15 - 2/15 = 3/5 x (7/9 - 2/9 )
= 1/3 = 3/5 x 5/9
= 1/3
c, Cách 1:(6/7 - 4/7) : 2/5 Cách 2: ( 6/7- 4/7 ) : 2/5
= 2/7 : 2/5 = 6/7 : 2/5 - 4/7 : 2/5
= 5/7 = 15/7 - 10/7
= 5/7
d,Cách 1:8/15 : 2/11 + 7/15 : 2/11 Cách 2:8/15 : 2/11 +7/15 : 2/11
= 88/30 + 77/30 =(8/15+7/15) :2/11
= 11/2 = 1 : 2/11
= 11/2
Bài 2 cậu tự làm nhé !
a) 1/2x(3/4+2/5)
1/2x23/20
23/40
b) 3/4:(8/9+16/3)
3/4:56/9
27/224
c) 1/5:1/10-1/3
2-1/3
5/3
d) 3/4x(20/9-8/15)
3/4x76/45
19/15
e) 1/7:5/14-3/2
=2/5-3/2
-11/10 ( Chị nghĩ lớp 4 chưa học đến số âm nên em xem lại đề nhé)
g) 3/2x(11/6-5/12)
3/2x17/12
17/8
a)\(\frac{1}{2}x\left(\frac{3}{4}+\frac{2}{5}\right)\)
\(=\frac{1}{2}x\left(\frac{15}{20}+\frac{8}{20}\right)\)
\(=\frac{1}{2}x\frac{23}{20}\)
\(=\frac{23}{40}\)
b)\(\frac{3}{4}:\left(\frac{8}{9}+\frac{16}{3}\right)\)
\(=\frac{3}{4}:\left(\frac{8}{9}+\frac{48}{9}\right)\)
\(=\frac{3}{4}:\frac{56}{9}\)
\(=\frac{3}{4}x\frac{9}{56}\)
\(=\frac{27}{224}\)
c) \(\frac{1}{5}:\frac{1}{10}-\frac{1}{3}\)
\(=\frac{1}{5}x10-\frac{1}{3}\)
\(=2-\frac{1}{3}\)
\(=\frac{6}{3}-\frac{1}{3}=\frac{5}{3}\)
d) \(\frac{3}{4}x\left(\frac{20}{9}-\frac{8}{15}\right)\)
\(=\frac{3}{4}x\left(\frac{100}{45}-\frac{24}{45}\right)\)
\(=\frac{3}{4}x\frac{76}{45}\)
\(=\frac{19}{5}\)
e) \(\frac{1}{7}:\frac{5}{14}-\frac{3}{2}\)
\(=\frac{1}{7}x\frac{14}{5}-\frac{3}{2}\)
\(=\frac{2}{5}-\frac{3}{2}\)
\(=\frac{4}{10}-\frac{15}{10}\)
\(=\frac{-11}{10}\)
g) \(\frac{3}{2}x\left(\frac{11}{6}-\frac{5}{12}\right)\)
\(=\frac{3}{2}x\left(\frac{22}{12}-\frac{5}{12}\right)\)
\(=\frac{3}{2}x\frac{17}{12}\)
=\(=\frac{17}{8}\)
a, (6/11+5/11)x3/17
c1:=1x3/17
=3/17
c2:=6/11x3/17+5/11x3/17
=18/197+15/187
=33/187
=3/17
b,3/5x7/9-3/5x2/9
c1:=21/45-6/45
=15/45
=1/3
c2:=3/5x(7/9-2/9)
=3/5x5/9
=1/3
c,( 6/7-4/7):2/5
c1:=2/7:2/5
=2/7x5/2
=5/7
c2,6/7:2/5-4/7:2/5
=6/7x5/2-4/7x5/2
=15/7-10/7
=5/7
d,8/15:2/11+7/15:2/11
c1:=(8/15+7/15):2/11
=1x11/2
=11/2
c2:=8/15x11/2+7/15x11/2
=88/30+77/30
=165/30
=11/2
a) (\(\frac{6}{11}\) + \(\frac{5}{11}\)) x \(\frac{3}{17}\)= \(\frac{11}{11}\) x \(\frac{3}{17}\)= \(1\) x\(\frac{3}{17}\)= \(\frac{3}{17}\)
b) \(\frac{3}{5}\)x\(\frac{7}{9}\)- \(\frac{3}{5}\)x \(\frac{2}{9}\) = \(\frac{3}{5}\)x (\(\frac{7}{9}\)- \(\frac{2}{9}\))= \(\frac{3}{5}\) x \(\frac{5}{9}\)= \(\frac{3}{9}\)
c) (\(\frac{6}{7}\)- \(\frac{4}{7}\)) : \(\frac{2}{5}\)= \(\frac{2}{7}\) x \(\frac{5}{2}\)= \(\frac{5}{7}\)
d) \(\frac{8}{15}\) : \(\frac{2}{11}\) + \(\frac{7}{15}\): \(\frac{2}{11}\)= ( \(\frac{8}{15}\)+ \(\frac{7}{15}\)) x \(\frac{11}{2}\)= 1 x \(\frac{11}{2}\)= \(\frac{11}{2}\)
Chúc học tốt nha!
a)\(=\dfrac{3}{3}+\dfrac{4}{3}=\dfrac{7}{3}\)
b)\(=\dfrac{5}{9}\times\dfrac{3}{2}=\dfrac{15}{18}=\dfrac{5}{6}\)
d)\(=\left(\dfrac{12}{8}-\dfrac{3}{8}\right)\times2=\dfrac{9}{8}\times2=\dfrac{18}{8}=\dfrac{9}{4}\)
c)\(=\dfrac{4}{3}-\dfrac{5}{6}=\dfrac{8}{6}-\dfrac{5}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)
a) 1 + 4/3 = 7/3
b) 5/9 : 2/3 = 5/6
c ) 4/3 -1/3 x 5/2
= 1 x 5/2
= 5/2
d) ( 3/2 - 3/8) : 1/2
= 9/8 : 1/2
= 9/4
e) 15/16 : 3/8 x 3/4
= 5/2 x 3/4
= 15/8
f) 7/19 x 1/3 x 7/19 x 2/3
= 7/19 x (1/3 x 2/3)
= 7/19 x 2/9
= 14/171
g) 3/5 x 8/27 x 25/3
= 3/5 x 25/3 x 8/27
= 5 x 8/27
= 40/27
h) 1/5 + 4/11 + 4/5 + 7/11
= (1/5 + 4/5) + (4/11 + 7/11)
= 1 + 1
= 2
\(a)\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{2}{5}=1+\frac{2}{5}=\frac{7}{5}\)
\(b)\frac{5}{7}.\frac{2}{3}.\frac{14}{15}=\frac{5.2.14}{7.3.15}=\frac{4}{9}\)
\(c)\frac{3}{8}+\frac{2}{5}.\frac{5}{8}=\frac{3}{8}+\frac{1}{4}=\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\)
\(d)\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{7}{15}=\frac{4}{15}\)
~Học tốt~
a) \(\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}+\frac{2}{5}=\frac{3+5}{8}+\frac{2}{5}\)
\(=1+\frac{2}{5}=\frac{5}{5}+\frac{2}{5}=\frac{7}{5}\)
b) \(\frac{5}{7}\times\frac{2}{3}\times\frac{14}{15}=\frac{5}{7}\times\frac{14}{15}\times\frac{2}{3}=\frac{5\times2\times7}{7\times3\times5}\times\frac{2}{3}\)
\(=\frac{2}{3}\times\frac{2}{3}=\frac{4}{9}\)
c) \(\frac{3}{8}+\frac{2}{5}\times\frac{5}{8}=\frac{3}{8}+\frac{2\times5}{5\times8}=\frac{3}{8}+\frac{2}{8}\)
\(=\frac{5}{8}\)
d) \(\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{2}{3}+\frac{1}{5}=\frac{11}{15}-\frac{2\times5}{3\times5}+\frac{3\times1}{3\times5}\)
\(=\frac{11}{15}-\frac{10}{15}+\frac{3}{15}=\frac{11-10+3}{15}=\frac{4}{15}\)