\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{3+6-2}{12}\)

\(=\frac{7}{12}\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{9}{12}-\frac{2}{12}\)

\(=\frac{7}{12}\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{7}{12}\)

\(2\frac{4}{3}+\frac{4}{12}=\frac{2.3+4}{3}+\frac{4}{12}=\frac{10}{3}+\frac{4}{12}=\frac{40}{12}+\frac{4}{12}=\frac{44}{12}=\frac{11}{3}\)

\(2\frac{4}{3}=\frac{10}{3}\)

\(\frac{10}{3}+\frac{4}{12}=\frac{120}{36}+\frac{12}{36}\)

\(=\frac{132}{36}=\frac{22}{6}=\frac{11}{3}\)

\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{110}\)

\(=\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{10\cdot11}\)

\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{10}-\frac{1}{11}\)

\(=\frac{1}{2}-\frac{1}{11}=\frac{9}{22}\)

= 1/2.3 +1/3.4+1/4.5+...+1/10.11

=1/2-1/3+1/3-1/4+1/4-1/5+...+1/10-1/11

=1/2-1/11

=9/22

~~~~~~~~~~~~ chúc bạn học thật giỏi~~~~~~~~~~~~~

Đặt A=1/6 + 1/12 + 1/20 +.........+1/110

A= 1/2x3 +1/3x4 +1/4x5 +......+ 1/10x11

A= 1/2-1/3 +1/3-1/4 +...........+ 1/10-1/11

A=(1/2-1/11) + (1/3 - 1/3) +.......+ (1/10 - 1/10)

A=11/22 -2/22 + 0 +...........+ 0

A=9/22

Vậy A= 9/22

x.18=99

x=99:18

x=5,5

x.9+x.9 = 12+87

2.x.9 = 99

x.18 = 99

x = 5,5

Vậy x=5,5

Nhớ k cho anh nhé!

5,5 nha bạn

mình nè

= 2x4/3x4 + 3x3/4x3 +3/12=8/12+9/12+3/12=8+9+3/12=20/12=5/3

dễ sợ thiệt

Mấy bạn dùng mấy cái này để xin đúng

  60   +   90    x    \(\frac{3}{5}\)

= 60     +         54

= 114

\(60+90\times\frac{3}{5}\)

\(=60+54=114\)

60+90 x 3/5=114

\(12\frac{4}{5}\)=\(\frac{64}{5}\).

Ta có :

\(\frac{64}{5}+\frac{4}{5}=\frac{68}{5}\)

\(12\frac{4}{5}+\frac{4}{5}=\frac{64}{5}+\frac{4}{5}=\frac{68}{5}\)

\(12\frac{4}{5}+\frac{4}{5}=\frac{12x5+4}{5}+\frac{4}{5}=\frac{64}{5}+\frac{4}{5}=\frac{68}{5}\)

\(\frac{12}{5}+\frac{23}{4}=\frac{48}{20}+\frac{115}{20}=\frac{163}{20}\)

\(=\frac{163}{20}\)

\(\frac{12}{5}+\frac{23}{4}\) 

\(=\frac{24}{20}+\frac{115}{20}\) 

\(=\frac{139}{20}\) 

\(12\frac{3}{7}\%+12\frac{5}{7}\%=\frac{176}{7}\%\)