Question

tính nhanh

\(\frac{1999\cdot2001-1}{1998+1999\cdot2000}\)x \(\frac{7}{5}\)

. là nhân

x là nhân

Answer 1

\(\frac{1999\cdot2001-1}{1998+1999\cdot2000}\cdot\frac{7}{5}\)

\(=\frac{1999\cdot\left(2000+1\right)-1}{1998+1999\cdot2000}\cdot\frac{7}{5}\)

\(=\frac{1999\cdot2000+1999-1}{1998+1999.2000}\cdot\frac{7}{5}\)

\(=\frac{1999\cdot2000+1998}{1998+1999.2000}\cdot\frac{7}{5}=1\cdot\frac{7}{5}=\frac{7}{5}\)

Answer 2

thank you very much

Answer 3

1999.2001-1/1998+1999.2000 x 7/5

=1999.2001-(1999-1998)/1998+1999.2000 x7/5

=1999.2001-1999+1998/1998+1999.2000 x7/5

=1999(2001-1)+1998/1998+1999.2000x7/5

=1999.2000+1998/1998+1999.2000x7/5

=1x7/5=7/5

Answer 4

k mình nha