\(\left[461+\left(-78\right)+40\right]+\left(-461\right)\\ =461+\left(-78\right)+40-461\\=\left(461-461\right)+\left(-78+40\right)\\ =0+\left(-38\right)\\ =-38\)

a,\(\frac{7}{10}\cdot\frac{4}{9}+\frac{3}{10}\cdot\frac{4}{9}-1\frac{7}{9}\)

\(=\frac{14}{45}+\frac{2}{15}-\frac{16}{9}\)

\(=\frac{14}{45}+\frac{6}{45}-\frac{80}{45}\)

\(=\frac{-60}{45}=\frac{-4}{3}\)

b,\(\frac{-5}{6}+\frac{4}{9}\cdot\left(\frac{5}{4}-\frac{2}{3}\right)\cdot\left(-3\right)^2+\frac{5}{9}\cdot30\%\)

\(=\frac{-5}{6}+\frac{4}{9}\cdot\left(\frac{7}{12}\right)\cdot9+\frac{5}{9}\cdot\frac{3}{10}\)

\(=\frac{-5}{6}+\frac{7}{3}+\frac{1}{6}\)

\(=\frac{-5}{6}+\frac{14}{6}+\frac{1}{6}\)

=\(=\frac{10}{6}=\frac{5}{3}\)

Giúp mình với mình đang vội!!

cứ bình tĩnh bạn ơi

$\frac{4^{10}{.9}^6+3^{12}{.8}^5}{}$

$\frac{6^{13}.4-2^{16}{.3}^{12}}{}$

$=$

$\frac{{\left(2^2\right)}^{10}.{\left(3^2\right)}^6+3^{12}.{\left(2^3\right)}^5}{{\left(2.3\right)}^{13}{.2}^2-2^{16}{.3}^{12}}$

$=$

$\frac{2^{20}{.3}^{12}+3^{12}{.2}^{15}}{}$

$\frac{2^{13}{.3}^{13}{.2}^2-2^{16}{.3}^{12}}{}$

$=$

$\frac{2^{20}{.3}^{12}+3^{12}{.2}^{15}}{}$

$\frac{2^{15}{.3}^{12}.3-3^{12}{.2}^{16}}{}$

$=$

$\frac{2^4}{3}$

 31 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 3 + 4 + 15 + 16 + 17 + 18 = 181

31 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 3 + 4 + 15 + 16 + 17 + 18=181

=181 nhé

1 / 9 + 2 / 9 + 4 / 9 = 7 / 9

5 / 5 + 6 / 5 + 1 = 15 / 5 = 3

12 / 2 + 4 / 2 + 1 + 3 / 2 = 21 / 2

7 / 3 + 6 / 3 + 1 + 1 = 19  / 3

1+2-3-4+5+6-7-8+9+................+33

=1+(2-3-4+5)+(6-7-8+9)+............+(30-31-32+33)

=1+0+0+..............+0

=1

Cảm ơn nha ! Kết bạn với tớ nhé!

1+2-3-3+5+6-7-8+9+10-11-12+13+...............+33

= 1 + ( 2-3-4+5)+(6-7-8+9)+......+(30-31-32+33)

=1

=(-1)

học 

tốt 

nha