=297+[1000+(-670)+(-330)]

=297+0

=297

= 1000 - 670 + 297 - 330

= 330 + 297 - 330

= 297 

=297 nha

ai k mk,mk k lai

a/ ( -500 ) + (-174) + 1999 + (-266) + ( - 1499 )

=[(-174)+(-266)]+[1999+(-1499)+(-500)]

=(-440)+0

=-440

b/ 1000 + ( - 670 ) + 2004 + ( -300 )

=2004+1000-970

=2004+30

=2034

\(a,A=\left(2^{17}+17^2\right)\left(9^{15}-3^{30}\right).\left(2^4-32^2\right)\)

\(\Rightarrow A=\left(2^{17}+17^2\right)\left(3^{30}-3^{30}\right).\left(2^4-32^2\right)\)

\(\Rightarrow A=\left(2^{17}+17^2\right).0.\left(2^4-32^2\right)\)

\(\Rightarrow A=0.\)

\(\Rightarrow B=\left(2^8.8^3\right):\left(2^5.2^3\right)\)

\(\Rightarrow B=\left(2^8.2^9\right):\left(2^5.2^3\right)\)

\(\Rightarrow B=2^{17}:2^8\)

\(\Rightarrow B=2^9\)

\(\Rightarrow B=512\)

\(c,C=64^4.16^5:4^{20}\)

\(\Rightarrow C=2^{24}.2^{20}:2^{40}\)

\(\Rightarrow C=2^4\)

\(\Rightarrow C=16\)

a: \(A=\left(2^{17}+17^2\right)\cdot\left(2^4-32^2\right)\cdot\left(3^{30}-3^{30}\right)=0\)

b: \(B=\dfrac{2^8\cdot2^9}{2^5\cdot2^3}=2^9\)

c: \(C=2^{24}\cdot2^{20}:2^{40}=2^4=16\)

ko biết

    110+220+330+440+560+670+780+890+500

   = (110+890)+(220+780)+(330+670)+(440+560)+500

   =  1000+1000+1000+1000+500

   =4500

Tính bằng cách thuận tiện nhất

110+220+330+440+560+670+780+890+500

Trả lời :

( 110  + 890 )  ( 220 +  780 ) +  ( 330 + 670 ) +  ( 440 +  560 )  +  560 +  500 = 

 1000 +    1000 +   1000 +    1000 +   560 + 500 =

   4000 + 1060 = 

    5060

^ HT ^

\(41\dfrac{8}{23}-\left(6\dfrac{7}{32}+15\dfrac{8}{23}\right)\)

\(=41\dfrac{8}{23}-6\dfrac{7}{32}-15\dfrac{8}{23}\)

\(=26-6\dfrac{7}{32}\)

\(=20-\dfrac{7}{32}\)

\(=\dfrac{633}{32}\)

\(41\dfrac{8}{23}-\left(6\dfrac{7}{32}+15\dfrac{8}{23}\right)\)

\(=41\dfrac{8}{23}-6\dfrac{7}{32}-15\dfrac{8}{23}\)

\(=26-6\dfrac{7}{32}\)

\(=20-\dfrac{7}{32}\)

\(=\dfrac{633}{32}\)

b) = (-461) - 363

= - 824

d) = (-1010) + 1000

= -10

Lời giải:
Gọi tổng trên là $A$
$A=2(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.11}+...+\frac{1}{100.103})$

$A=\frac{2}{3}(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.11}+...+\frac{3}{100.103})$

$=\frac{2}{3}(\frac{4-1}{1.4}+\frac{7-4}{4.7}+...+\frac{103-100}{100.103})$

$=\frac{2}{3}(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+....+\frac{1}{100}-\frac{1}{103})$

$=\frac{2}{3}(1-\frac{1}{103})$

$=\frac{2}{3}.\frac{102}{103}=\frac{68}{103}$

Bạn Akai Haruma đáp án của bạn đúng khi phân số 1/7*11 là 1/7*10