?

= 43/44

Đáp án : 43/44

= \(\dfrac{2}{7}\) - \(\dfrac{-3}{11}\)+\(\dfrac{5}{7}\)-\(\dfrac{-1}{4}\)- \(\dfrac{6}{11}\)

= (\(\dfrac{2}{7}\)+\(\dfrac{5}{7}\)) - ( \(\dfrac{-3}{11}\)+ \(\dfrac{6}{11}\)) - \(\dfrac{-1}{4}\)

= 1 - \(\dfrac{3}{11}\)-\(\dfrac{-1}{4}\)

= \(\dfrac{44}{44}\)-\(\dfrac{12}{44}\)-\(\dfrac{-11}{44}\)

= \(\dfrac{43}{44}\)

6/21-(−12/44)+10/14−(1/(−4))−18/33

=2/7+12/44+5/7−((−1)/4)−6/11=2/7+12/44+5/7−((−1)/4)−6/11

=2/7+3/11+5/7+1/4−6/11=2/7+3/11+5/7+1/4−6/11

=(3/11−6/11)+(2/7+5/7)+1/4=(3/11−6/11)+(2/7+5/7)+1/4

=−3/11+7/7+1/4=−3/11+7/7+1/4

=43/44

\(=4+\dfrac{1}{6}-2-\dfrac{1}{3}+3+\dfrac{7}{12}-5-\dfrac{3}{4}\)

\(=\dfrac{1}{6}-\dfrac{1}{3}+\dfrac{7}{12}-\dfrac{3}{4}=\dfrac{2}{12}-\dfrac{4}{12}+\dfrac{7}{12}-\dfrac{9}{12}=0\)

\(=4+\dfrac{1}{6}-2-\dfrac{1}{3}+3+\dfrac{7}{12}-5-\dfrac{3}{4}\)

\(=\left(4-2+3-5\right)+\left(\dfrac{1}{6}-\dfrac{1}{3}+\dfrac{7}{12}-\dfrac{3}{4}\right)\)

\(=0+\dfrac{2-4+7-9}{12}\)

\(=\dfrac{-4}{12}=\dfrac{-1}{3}\)

a: =-21/36-3/36=-24/36=-2/3

b: =43/12*1/2+5/24=43/24+5/24=2

c: =8/9+1/9=1

e: =1-1/4+1/4-1/7+...+1/97-1/100

=1-1/100=99/100

=(2/7+5/7)+(3/11-6/11)+1/4

=5/4-3/11

=55/44-12/44=43/44

Gợi ý: Sử dụng tính chất phân phối của phép nhân đối với phép cộng để nhóm thừa số chung ra ngoài.

=(2/7+5/7)+(3/11-6/11)+1/4

=5/4-3/11=55/44-12/44=43/44

a)P=\(\dfrac{-2}{7}+\dfrac{14}{29}+\dfrac{12}{33}+\dfrac{15}{29}+\dfrac{21}{33}+\dfrac{2}{7}\)

      =\(\left(\dfrac{-2}{7}+\dfrac{2}{7}\right)+\left(\dfrac{14}{29}+\dfrac{15}{29}\right)+\left(\dfrac{12}{33}+\dfrac{21}{33}\right)\)

      =0+1+1=2

b)\(\dfrac{2}{7}.\dfrac{5}{19}+\dfrac{2}{7}.\dfrac{14}{19}+\dfrac{21}{19}-\dfrac{2}{7}.\dfrac{1}{5}\)

=\(\dfrac{2}{7}.\left(\dfrac{5}{19}+\dfrac{14}{19}-\dfrac{1}{5}\right)+\dfrac{21}{19}\)

=\(\dfrac{2}{7}.\dfrac{4}{5}+\dfrac{21}{19}=\dfrac{887}{665}\)