\(\frac{1998\times1996+1997+1995}{1996\times\left(1997-1995\right)}=\frac{1998\times1996+1996+1996}{1996\times2}=\frac{1996\times1999+1996}{1996\times2}\)

=\(\frac{1996\times2000}{1996.2}=\frac{2000}{2}=1000\)

\(A=\frac{1998.1996+1997.11+1985}{1997.1996-1995.1996}\)

\(A=\frac{1998.1996+\left(1996+1\right).11+1985}{1996.\left(1997-1995\right)}\)

\(A=\frac{1998.1996+1996.11+11+1985}{1996.2}\)

\(A=\frac{1998.1996+1996.11+1996}{1996.2}\)

\(A=\frac{1996.\left(1998+1+1\right)}{1996.2}\)

\(A=\frac{1996.2000}{1996.2}=1000\)

\(\frac{1998\times1996+1996\times11+1996}{1996\times2}\)\(=\frac{2010\times1996}{2\times1996}=1005\)

k nha

\(\frac{2}{7}\)+ \(\frac{5}{14}\)+\(\frac{1}{7}\)+ \(\frac{3}{14}\)=\(\frac{4}{14}\)+\(\frac{5}{14}\)+\(\frac{2}{14}\)+\(\frac{3}{14}\)=\(\frac{14}{14}\)=1

469x281+489x719=469x281+(469+20)x719=469x281+469x719+20x719=469x(281+719)+1438=469x1000+1438=469000+1438=470438

a\(\frac{2}{5}\)+\(\frac{5}{14}\)+\(\frac{1}{7}\)+\(\frac{3}{14}\)=\(\frac{53}{70}\)+\(\frac{1}{7}\)=\(\frac{9}{10}\)+\(\frac{3}{14}\)=\(\frac{39}{35}\)

b\(\frac{1995.1997-1}{1996.1995+1994}\)=3984008001

c    469x281+489x719

=(489-469)x(281+719)

=20x1000

=20000

\(B=\)\(\frac{3+33+333+3333+33333}{4+44+444+4444+44444}\)

\(B=\frac{3.1+3.11+3.111+3.1111+3.11111}{4.1+4.11+4.111+4.1111+4.11111}\)

\(B=\frac{3.\left(1+11+111+1111+11111\right)}{4.\left(1+11+111+1111+11111\right)}\)

\(B=\frac{3}{4}\)

\(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}\)

\(A.2=\left(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}\right).2\)

\(A.2=\frac{2}{3}+\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\)

=>\(A.2-A=\left(\frac{2}{3}+\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\right)-\left(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}\right)\)

\(A=\frac{2}{3}-\frac{1}{192}\)

\(A=\frac{127}{192}\)

\(\frac{1995}{1997}.\frac{1990}{1993}.\frac{1997}{1994}.\frac{1993}{1995}.\frac{997}{995}\)

Đặt \(C=\frac{1995}{1997}.\frac{1990}{1993}.\frac{1997}{1994}.\frac{1993}{1995}.\frac{997}{995}\)

      \(C=\frac{1995.1990.1997.1993.997}{1997.1993.1994.1995.995}\)

      \(C=\frac{1990.997}{1994.995}\)

      \(C=\frac{995.2+997}{997.2+995}=1\)

\(B=\frac{3+33+333+3333+ 33333}{4+44+444+4444+44444}\)

\(\Rightarrow B=\frac{3\left(1+11+111+1111+11111\right)}{4\left(1+11+111+1111+11111\right)}=\frac{3}{4}\)

1988/1996

Hok tốt !!

=\(\frac{1988x1996+1996+1996}{1996x\left(1997-1995\right)}\)=\(\frac{1996x\left(1988+2\right)}{1996x2}\)

=\(\frac{1996x1990}{1996x2}\)=\(\frac{1990}{2}\)=\(995\)

Hello!!!

1994 /1996

a, 9985

b, 21,86

c, \(\frac{23}{8}\)

a)9885

b)21.95

c)23/8