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![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
(-257)-{(-257+156)-56}
<=> (-257)-(-101-56)
<=> (-257)-(-157)
<=> -100
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 5 16 − 7 13 − 3 16 + − 6 13 = 5 16 − 3 16 + − 7 13 + − 6 13 = 1 8 + − 1 = − 7 8
b) − 5 12 − 3 4 + 7 12 − 2 8 = − 5 12 − 3 4 − 7 12 + 2 8 = − 5 12 − 7 12 + − 3 4 + 2 8 = − 1 + − 1 2 = − 3 2
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 3 3 .3 4 : 3 2 = 3 5
b) 5 16 : 5 14 .4 = 5 2 .4 = 100
c) 58.75 + 58.25 − 2 3 .10 2 = 58.100 − 800 = 5000
![](https://rs.olm.vn/images/avt/0.png?1311)
(-257)-[(-257+156)-56]
=(-257)-(-257+156-56)
=(-257)-(-257+100)
=-257+257-100
=(-257+257)-100
=0-100
=-100
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 5 16 : 0 , 125 − 2 1 4 − 0 , 6 . 10 11 = 5 16 : 1 8 − 9 4 − 3 5 . 10 11 = 155 11
b) 1 13 15 .0 , 75 − 11 20 + 25 % = 28 15 . 3 4 − 11 20 + 1 4 = 3 5
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 5 6 : 0 , 125 − 2 1 4 − 0 , 6 . 10 11 = 5 6 : 1 8 − 9 4 − 3 5 . 10 11 = 155 11
b) 1 , 4. 15 19 − 4 5 + 2 3 : 2 1 5 = 7 5 . 15 19 − 22 15 : 11 5 = 21 19 − 2 3 = 25 57
![](https://rs.olm.vn/images/avt/0.png?1311)
Theo quy tắc của dấu ngoặc,ta có:
516+320+357+5000+612-(516+320)-(5000+357+612)+(-420)+(-580)
= 516+320+357+5000+612-516-320-5000-357-612+(-420)+(-580)
= (516-516)+(320-320)+(357-357)+(5000-5000)+(612-612)+(-420)+(-580)
= 0 + 0 + 0 + 0 + 0 + (-420)+(-580)
= 0 + 0 + 0 + 0 + (-420)+(-580)
= 0 + 0 + 0 + (-420)+(-580)
= 0 + 0 + (-420)+(-580)
= 0 + ((-420)+(-580))
= 0 + -1000
= -1000
![](https://rs.olm.vn/images/avt/0.png?1311)
ta có :
4 chia hết cho 2 => 4.5.7 chia hết cho 2
516 chia hết cho 2
=> 4.5.7 + 516 chia hết cho 2 và 4.5.7 + 516 > 2
=>4.5.7 + 516 là hợp số
![](https://rs.olm.vn/images/avt/0.png?1311)
a ) 1 4 b ) − 29 28 . c ) 1 3 . d ) − 61 72 e ) 7 2 f ) − 13 4
tính hợp lý nếu có thể
a) 2.25.9.4
b)35.112-12.35+50
c)16+(516 : 514 - 90)
d) 24.7 - [181 - ( 13 - 4)2 ]
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(2\cdot25\cdot9\cdot4=25\cdot4\cdot9\cdot2=18\cdot100=1800\)
b: \(35\cdot112-12\cdot35+50\)
\(=35\left(112-12\right)+50\)
=3500+50
=3550
c: \(16+\left(5^{16}:5^{14}-9^0\right)\)
\(=16+5^2-1\)
=25+15
=40
d: \(24\cdot7-\left[181-\left(13-4\right)^2\right]\)
\(=168-181+9^2\)
=81-13
=68
a)2.25.9.4
=(25.4).(9.2)
=100.18
1800
b)35.112-12.35+50
=35.(112-12)+50
=35.100+50
=3500+50
=3550
c)\(16+\left(5^{16}:5^{14}-9^0\right)\)
\(=16+\left(5^2-9^0\right)\)
\(=16+\left(25-1\right)\)
\(=16+24\)
\(=40\)
d)\(24.7-[181-\left(13-4\right)^2]\)
\(=24.7-[181-9^2]\)
\(=24.7-[181-81]\)
\(=24.7-100\)
\(=168-100\)
\(=68\)
\(\frac{50^{15}.13^{18}}{25^7.26^{15}.5^{16}}=\frac{\left(5.5.2\right)^{15}.13^{18}}{\left(5.5\right)^7.\left(13.2\right)^{15}.5^{16}}=\frac{5^{15}.5^{15}.2^{15}.13^{18}}{5^7.5^7.13^{15}.2^{15}.5^{16}}=\frac{5^{30}.2^{15}.13^{18}}{5^{30}.13^{15}.2^{15}}=13^3=2197\)