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: \(36^2-52\cdot36+26^2=10^2=100\)

78/84=13/14

55/99=5/9

100/175=4/7

204/132=17/11

78/34 = 13/14

55/99 = 5/9

100/175 = 4/7

204/132 = 17/11

Chúc bạn học tốt !

a ) 25 - ( - 75 ) + 32 - ( 32 + 75

= 25 + 75 + 32 - 32 - 75

= 100 + 0 - 75

= 25

b ) 24 . ( 16 - 5 ) - 16 . ( 24 - 15 )

= 24 . 11 - 16 . 9

= 264 - 144

= 120

c ) 29 . ( 19 - 13 ) - 19 - ( 29 - 13 )

29 . 6 - 19 - 29 + 13

= 174 - 19 - 29 + 13

= 126 + 13

= 139

d ) ( 55 + 45 15 ) - ( 15 - 55 + 45 )

= 4570 - 15 + 10

= 4555 + 10

= 4565

- Cái này dùng Quy Tắc Phá Ngoặc

(45+75)*66+(75+45)*34

=(45+75)*(66+34)

=120*100

=12000

11+22+33+44+55+66+77+88+99:11

=11+22+33+44+55+66+77+88+9

=(11+9)+(22+88)+(33+77)+(44+66)+55

=20+110*3+55

=20+330+55

=405

Ta có :

a, (45 + 75) x 66 + (75 + 45) x 34

=  (45 + 75) x (66 + 34)

=   120  x 100

=  12000

11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 + 99 : 11

= 33 + 77 + 121 + 165 + 9

= 405

a, 1 + 2 + 3 + ... + 87

= (1 + 87).87 : 2

= 87.88 : 2

= 87.44

= 3828

b, 2 + 4 + 6 + ... + 54

= (2 + 54).27 : 2

= 27.56 : 2

= 27.28

= 756

c,  3 + 6 + 9 + ... + 99

= (99 + 3).49 : 2

= 49.102 : 2

= 49.51

= 2499

d, 45.25 + 45.75 + 55.25.25 + 55.75

= 45. (25 + 75) + 55(25.25 + 75)

= 45.100 + 55.700

= 4500 + 38500

= 43000

\(d,45x25+45x75+55x25+55x75\)

\(=45x\left(25+75\right)+55x\left(25+75\right)\)

\(=45x100+55x100\)

\(=100x\left(45+55\right)\)

\(=100x100\)

\(=10000\)