1,  17.( 85+15) -120 = 17. 100 -120 =1700 - 120 =1580

2, 

2³ . 17 - 2³ . 14

= 2³(17-14)

=2³. 3= 24

Giải:

a) \(2\dfrac{17}{20}-1\dfrac{15}{11}+6\dfrac{9}{20}:3\)

\(=\dfrac{57}{20}-\dfrac{26}{11}+\dfrac{129}{20}:3\) 

\(=\dfrac{107}{220}+\dfrac{43}{20}\)

\(=\dfrac{29}{11}\)

b) \(4\dfrac{3}{7}:\left(\dfrac{7}{5}.4\dfrac{3}{7}\right)\) 

\(=\dfrac{31}{7}:\left(\dfrac{7}{5}.\dfrac{31}{7}\right)\) 

\(=\dfrac{31}{7}:\dfrac{31}{5}\) 

\(=\dfrac{5}{7}\) 

c) \(\left(3\dfrac{2}{9}.\dfrac{15}{23}.1\dfrac{7}{29}\right):\dfrac{5}{23}\) 

\(=\left(\dfrac{29}{9}.\dfrac{15}{23}.\dfrac{36}{29}\right):\dfrac{5}{23}\) 

\(=\dfrac{60}{23}:\dfrac{5}{23}\) 

\(=12\)

a: \(17\cdot85+15\cdot17-120\)

\(=17\left(85+15\right)-120\)

=1700-120

=1580

b: \(2^3\cdot17-2^3\cdot14\)

\(=2^3\left(17-14\right)\)

\(=8\cdot3=24\)

c: \(20-\left\lbrack30-\frac{\left(5-1\right)^2}{2}\right\rbrack\)

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

\(=-10+\frac{16}{2}=-10+8=-2\)

d: \(80-\left(4\cdot5^2-3\cdot2^2\right)\)

\(=80-\left(4\cdot25-3\cdot4\right)\)

=80-100+12

=92-100

=-8

e: \(27\cdot77+24\cdot27-27\)

\(=27\left(77+24-1\right)\)

\(=27\cdot100=2700\)

f: \(174:\left\lbrace2\cdot\left\lbrack36+\left(4^2-23\right)\right\rbrack\right\rbrace\)

\(=\frac{174}{2\cdot\left(36+16-23\right)}=\frac{87}{52-23}=\frac{87}{29}=3\)

a: =125-24-75

=50-24

=26

a) \(=300\)

b) \(=374\)

c) \(=4747\)

d) \(=180000\)

a)300

b)374

a) Kết quả -70.          b) Kết quả 110.

a) 5² . 2 - 3² . 4           b) 58 . 75 + 58. 50 - 58 . 25

= 25 . 2 - 9 . 4              = 58 . ( 75 + 50 - 25 )

= 50 - 36                      = 58 . 100

= 14                             = 5800

a) 5² . 2 - 3² . 4           b) 58 . 75 + 58. 50 - 58 . 25

= 25 . 2 - 9 . 4              = 58 . ( 75 + 50 - 25 )

= 50 - 36                      = 58 . 100

= 14                             = 5800