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43/57 . 2/6 . ( 630 - 315 . 2 )

= 43/57 . 2/6 . ( 630 - 630 )

= 43/57 . 2/6 . 0

= 43/57 . 0

= 0

45 . 16 - 17

= 720 - 17 

= 703

45 . 15 + 28

= 675 + 28 

= 703

104 . 68 - 36 . 52 = 52 + 52 . 68 - 36 . 52

                            = 52 ( 1 + 68 - 36 )

                            = 52 . 33

                             = 85

45 . 15 + 28 = 675 + 28 

                     = 703 

45 . 16 - 17 = 720 - 17 = 703

a: \(61\cdot45+61\cdot23-68\cdot51\)

\(=61\left(45+23\right)-68\cdot51\)

\(=68\cdot61-68\cdot51\)

\(=68\left(61-51\right)=68\cdot10=680\)

b: \(3\cdot5^2-\left(75-4\cdot2^3\right)\)

\(=75-75+4\cdot8\)

\(=4\cdot8=32\)

c: \(36:\left\{2^2\cdot5-\left[30-\left(5-1\right)^2\right]\right\}\)

\(=\dfrac{36}{20-30+4^2}\)

\(=\dfrac{36}{-10+16}=\dfrac{36}{6}=6\)

d: \(\left(12\cdot49-3\cdot2^2\cdot7^2\right):\left(2020\cdot2021\right)\)

\(=\dfrac{\left(12\cdot49-12\cdot49\right)}{2020\cdot2021}=0\)

300

465 

104.68-36.52

=104.68-18.2.52

=104.68-18.104

=(68-18)104

=50.2.52

=100.52=5200

104.68-36.52

=52.2.68-36.52

=52.136-36.52

=52.(136-36)

=52.100

=5200

a: Sửa đề: \(17\cdot58\cdot43+57\cdot17\cdot28\)

\(=17\times\left(58\times43+57\times28\right)\)

=17x4090

=69530

b: Sửa đề: \(43\times53-2,6\times\left(630-315\times2\right)\)

=43x53-2,6x(630-630)

=43x53

=2279

c: \(\frac{45\times16-17}{45\times15+28}\)

\(=\frac{45\times15+45-17}{45\times15+28}\)

\(=\frac{45\times15+28}{45\times15+28}\)

=1

d: 104x68-36x52

=52x2x68-36x52

=52x136-36x52

=52x(136-36)

=52x100

=5200

a: \(2004^2-16\)

\(=\left(2004-4\right)\left(2004+4\right)=2000\cdot2008=4016000\)

b: \(892^2+892\cdot216+108^2\)

\(=892^2+2\cdot892\cdot108+108^2\)

\(=\left(892+108\right)^2=1000^2=1000000\)

c: \(36^2+26^2-52\cdot36\)

\(=36^2-2\cdot36\cdot26+26^2\)

\(=\left(36-26\right)^2=10^2=100\)

d: \(\left(10,2\cdot9,8-9,8\cdot0,2\right)+\left(10,22-10,2\cdot0,2\right)\)

\(=9,8\left(10,2-0,2\right)+10,22-2,04\)

=98+8,18

=106,18

e: \(20,03\cdot45+20,03\cdot47+20,03\cdot8\)

\(=20,03\cdot\left(45+47+8\right)\)

\(=20,03\cdot100=2003\)

g: \(15,75\cdot175-15,75\cdot55-15,75\cdot20\)

\(=15,75\cdot\left(175-55-20\right)\)

\(=15,75\cdot100=1575\)

h: \(A=57^2+114\cdot43+43^2\)

\(=57^2+2\cdot57\cdot43+43^2\)

\(=\left(57+43\right)^2=100^2=10000\)

i: \(B=5^4\cdot3^4-\left(15^2-1\right)\left(15^2+1\right)\)

\(=15^4-\left(15^4-1\right)=1\)

k: \(C=50^2-49^2+48^2-47^2+\cdots+2^2-1^2\)

\(=\left(50-49\right)\left(50+49\right)+\left(48-47\right)\left(48+47\right)+\cdots+\left(2-1\right)\left(2+1\right)\)

=50+49+...+2+1

\(=50\cdot\frac{51}{2}=25\cdot51=1225\)

a: \(2004^2-16=2000\cdot2008=4016000\)

b: \(892^2+892\cdot216+108^2=1000^2=1000000\)

c: \(36^2-52\cdot36+26^2=10^2=100\)