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\(\frac{4}{13}+\frac{9}{5}=\frac{137}{65}\)
\(3-\frac{2}{16}=\frac{23}{8}\)
\(\frac{12}{31}\times\frac{1}{19}=\frac{12}{589}\)
\(\frac{3}{8}\div\frac{9}{12}=\frac{1}{2}\)
a) $\frac{1}{6} \times \frac{2}{3} = \frac{{1 \times 2}}{{6 \times 3}} = \frac{2}{{18}} = \frac{1}{9}$
b) $\frac{6}{5} \times \frac{3}{8} = \frac{{6 \times 3}}{{5 \times 8}} = \frac{{18}}{{40}} = \frac{9}{{20}}$
c) $\frac{4}{3} \times \frac{8}{9} = \frac{{4 \times 8}}{{3 \times 9}} = \frac{{32}}{{27}}$
d) $\frac{5}{{12}} \times \frac{{12}}{5} = \frac{{5 \times 12}}{{12 \times 5}} = \frac{{60}}{{60}} = 1$
a) $\frac{1}{6}:\frac{3}{7} = \frac{1}{6} \times \frac{7}{3} = \frac{7}{{18}}$
b) $\frac{5}{{12}}:\frac{1}{4} = \frac{5}{{12}} \times \frac{4}{1} = \frac{{5 \times 4}}{{12 \times 1}} = \frac{{5 \times 4}}{{4 \times 3 \times 1}} = \frac{5}{3}$
c) $\frac{4}{{15}}:\frac{8}{3} = \frac{4}{{15}} \times \frac{3}{8} = \frac{{4 \times 3}}{{15 \times 8}} = \frac{{4 \times 3}}{{5 \times 3 \times 4 \times 2}} = \frac{1}{{10}}$
d) $\frac{{18}}{5}:\frac{9}{{10}} = \frac{{18}}{5} \times \frac{{10}}{9} = \frac{{18 \times 10}}{{5 \times 9}} = \frac{{9 \times 2 \times 5 \times 2}}{{5 \times 9}} = 4$
a) x+ \(\frac{4}{5}\)= \(\frac{4}{5}\)+ ( \(\frac{3}{7}\)+ \(\frac{3}{5}\))
x + \(\frac{4}{5}\)= \(\frac{4}{5}\)+ \(\frac{36}{35}\)
=> x = \(\frac{36}{35}\)
Vậy : x = \(\frac{36}{35}\)
b) \(\frac{4}{9}\)+\(\frac{8}{9}\)+ \(\frac{12}{9}\)+ ... + \(\frac{56}{9}\)
= \(\frac{4+8+12+...+56}{9}\)
Ta có : 4+8+12 + ... +56
Số các số hạng của dẫy số trên là : ( 56 -4) + 4 +1 = 14 ( số hạng )
=> Tổng trên = ( 4+56) x 14 : 2 = 420
=> \(\frac{4}{9}\)+ \(\frac{8}{9}\)+ ... + \(\frac{56}{9}\)= \(\frac{420}{9}\)= \(\frac{140}{3}\)
a)x=3/7+3/5=3x(1/7+1/5)=36/35
b)=(4+8+...+56)/9=(56+4)x14/9=280/3
a) $\frac{2}{7}:\frac{4}{9} = \frac{2}{7} \times \frac{9}{4}$
b) $\frac{{12}}{{25}}:\frac{6}{5} = \frac{{12}}{{25}} \times \frac{5}{6}$
c) $\frac{5}{8}:3 = \frac{5}{8}:\frac{3}{1} = \frac{5}{8} \times \frac{1}{3}$
a)\(\frac{2}{3}:\frac{4}{9}+\frac{1}{3}:\frac{4}{9}\)
=\(\frac{4}{9}:\left(\frac{2}{3}+\frac{1}{3}\right)\)
=\(\frac{4}{9}:1=\frac{4}{9}\)
b
a)\(\frac{16}{20}=\frac{4}{5};\frac{9}{15}=\frac{3}{5}\)
Vì 4>3\(\Rightarrow\frac{4}{5}>\frac{3}{5}\) hay \(\frac{16}{20}>\frac{9}{15}\)
Vậy \(\frac{16}{20}>\frac{9}{15}\)
b) \(\frac{6}{8}=\frac{3}{4};\frac{3}{12}=\frac{1}{4}\)
Vì 3>1 \(\Rightarrow\frac{3}{4}>\frac{1}{4}\) hay \(\frac{6}{8}=\frac{3}{12}\)
Vậy \(\frac{6}{8}=\frac{3}{12}\)
c) \(\frac{15}{25}=\frac{3}{5};\frac{36}{45}=\frac{4}{5}\)
Vì 3<4 \(\Rightarrow\frac{3}{5}<\frac{4}{5}\) hay \(\frac{15}{25}<\frac{36}{45}\)
Vậy \(\frac{15}{25}<\frac{36}{45}\)
bn ơi hình như chả có cái nào đúng cả
thanks bn
otaku than thanh nha!!!!!!!!!!!!!!!!!