32.47+47.68- 100 . 17

= (32.47+47.68) - 100 . 17

= 47 (32 + 68) - 100.17

= 47.100 - 100.17

= 100.(47-17)

= 100. 30

= 3000

  32.47+47.68- 100 . 17

= 47. ( 32+68 ) - 100.17

=47.100 - 100.17

=100.( 47-17 )

=100.30

=3000

32.47+47.68-100.17

=47.(32+68)-100.17

=47.100-100.17

=100.(47-17)

=100.30

=3000.

=1001

=1001

\(a,S_3=-2-2-...-2\)

Tổng có \(\left[\left(2003-1\right):2+1\right]:2=501\left(số.hạng\right)\)

\(\Rightarrow S_3=501\cdot\left(-2\right)=-1002\)

\(b,S_4=\left(-1001+1001\right)+\left(-1000+1000\right)+...+\left(-1+1\right)+1002\\ S_4=1002\)

a: \(S_3=1+\left(-3\right)+5+\left(-7\right)+...+2001+\left(-2003\right)\)

=(-2)+(-2)+...+(-2)

=-2004

\(\left(9^{98}\cdot80+9^{98}\right):9^{100}\)   

\(=\frac{9^{98}\cdot80+9^{98}}{9^{100}}\)   

\(=\frac{9^{98}\cdot\left(80+1\right)}{9^{100}}\)   

\(=\frac{9^{98}\cdot81}{100}\)  

\(=\frac{9^{98}\cdot9^2}{9^{100}}\)   

\(=\frac{9^{100}}{9^{100}}=1\)

đáp án bằng 1

Bạn có thể nào cho lời giải được không?

\(=\dfrac{9^3\cdot\left(2^3\cdot3+45\right)}{9^3}=8\cdot3+45=69\)

hợp lí nhất là tính trong ngoặc trước:)

   100:{250:[450-(500-\(2^2\).25)]}

=100:{250:[450-(500-4.25)]}

=100:{250:[450-(500-100)]}

=100:{250:[450-400]}

=100:{250:50}

=100:50

=2

100:(250:[450-(500-4.25)]

=100:(250:(450-(500-100)]

=100:(250:(450-400)]

=100:(250:50)

=100:5

=20

100: {250:[ 450 - ( 500 - 2^2. 25 )]}

= 100 : { 250 : [ 450 - ( 500 - 4 . 25 )]}

= 100 : { 250 : [ 450 - ( 500 - 100 )]}

= 100 : { 250 : [450 -  400 ]}

= 100 : { 250 : 50 }

= 100 : 50

= 2

c: \(=5+\dfrac{6}{7}-2-\dfrac{3}{8}-1-\dfrac{1}{8}=2+\dfrac{6}{7}-\dfrac{1}{2}=\dfrac{3}{2}+\dfrac{6}{7}=\dfrac{33}{14}\)

e: \(=\dfrac{-3}{5}\left(-\dfrac{1}{9}-\dfrac{5}{6}+\dfrac{5}{2}\right)=\dfrac{-3}{5}\cdot\dfrac{14}{9}=\dfrac{-14}{15}\)