#\(N\)

`a, -677*54+54.(-125)+2.54`

`=54.(-677+-125+2)`

`=54.(-800)`

`=-43200`

`b, -(324-267+252)+(133-76)`

`=-324+267-252+133-76`

`= (-324+-76)+(133+267)-252`

`=-400+400-252`

`=-252`

a: =54(-677-125+2)

=54*(-800)

=-43200

b: =-324+267-252+133-76

=-400+400-252

=-252

a. -677 . 54 + 54 . ( - 125 ) + 2. 54

= 54 . ( -677 + ( -125 ) + 2 )

= 54 . ( -802 + 2 )

= 54 . ( -800 )

= -43200

b.- (324 - 267 + 252) + (133 - 76)

= 324 - 267 + 252 + 133 -76

= 324 +76 - 267 + 133 -252

= 400 - 400 +252

= -252

a) \(45^2+33^2-22^2+90.33\)

\(=\)\(\left(45^2+33^2+2.45.33\right)-22^2\)

\(=\left(45+33\right)^2-22^2\)

\(=\left(45+33+22\right)\left(45+33-22\right)\)

\(=100.56\)

\(=5600\)

327 - 16 + 216 - 27 + 600          16 x 48 + 8 x 48 + 16 x 28

=(327 - 27) + (216 - 16) + 600      =16 x 48 + 16 x 24 + 16 x 28 

=300           + 200           + 600     =16 x (48 + 24 + 28)

=500                               + 600     =16 x 100

=1100                                            =1600

=72x100=7200

=72x100=7200

a: \(=\dfrac{5}{9}\cdot\dfrac{7}{4}+\dfrac{13}{9}\cdot\dfrac{7}{4}=\dfrac{7}{4}\cdot2=\dfrac{7}{2}\)

b: \(=\dfrac{14}{13}\cdot2+\dfrac{3}{13}\cdot2-2\cdot\dfrac{7}{13}=\dfrac{28}{13}+\dfrac{6}{13}-\dfrac{14}{13}=\dfrac{20}{13}\)

Ta có: \(A=1+\dfrac{1}{8}+\dfrac{1}{24}+\dfrac{1}{48}+\dfrac{1}{80}+\dfrac{1}{120}\)

\(\Leftrightarrow2A=2+\dfrac{2}{2\cdot4}+\dfrac{2}{4\cdot6}+\dfrac{2}{6\cdot8}+\dfrac{2}{8\cdot10}+\dfrac{2}{10\cdot12}\)

\(\Leftrightarrow2A=2+\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{10}-\dfrac{1}{12}\)

\(\Leftrightarrow2A=2+\dfrac{1}{2}-\dfrac{1}{12}\)

\(\Leftrightarrow2A=\dfrac{24}{12}+\dfrac{6}{12}-\dfrac{1}{12}\)

\(\Leftrightarrow2A=\dfrac{29}{12}\)

hay \(A=\dfrac{29}{24}\)

A=1+1/2+1/3+1/6+(1/12+1/15+1/20+1/30)+1/35

=71/35+7/30=95/42

a) \(\left(145\times99+145\right)-\left(143\times102-143\right)\)

\(=\left[145\times\left(99+1\right)\right]-\left[143\times\left(102-1\right)\right]\)

\(=\left(145\times100\right)-\left(143\times101\right)\)

\(=14500-14443\)

\(=57\)

b) \(54\times47-47\times53-20-27\)

\(=47\times\left(54-53\right)-20-27\)

\(=47-20-27\)

\(=0\)

c) \(10000-47\times72-47\times28\)

\(=10000-47\times\left(72+28\right)\)

\(=10000-47\times100\)

\(=10000-4700\)

\(=5300\)

d) \(3457-27\times48-48\times73+6543\)

\(=\left(3457+6543\right)-48\times\left(27+73\right)\)

\(=10000-48\times100\)

\(=10000-4800\)

\(=5200\)