`6/21-(-12/44)+10/14-(1/(-4))-18/33`

`=2/7+12/44+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+7/7+1/4`

`=43/44`

?

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

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

= \(\dfrac{43}{44}\)

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

=5/4-3/11

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

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

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

\(\frac{6}{21}-\left(-\frac{12}{44}\right)+\frac{10}{14}-\frac{1}{-4}-\frac{18}{33}\)

\(=\frac{3}{7}-\left(-\frac{3}{11}\right)+\frac{5}{7}+\frac{1}{4}-\frac{6}{11}\)

sai đề

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

áp dụng kiến thức tính nhanh ý

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275

= 1275