1. Tính:
a) 25 + ( - 13 + 8 );
b) 7 + ( - 12 + 43 ) - [ 2 + ( 19 - 34)]
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a) \(\dfrac{{ - 1}}{{13}} + \dfrac{9}{{13}}\)
\( = \dfrac{{ - 1 + 9}}{{13}} = \dfrac{8}{{13}}\)
b) \(\dfrac{{ - 3}}{8} + \dfrac{5}{{12}}\)
\(\begin{array}{l} = \dfrac{{ - 3.3}}{{8.3}} + \dfrac{{5.2}}{{12.2}}\\ = \dfrac{{ - 9}}{{24}} + \dfrac{{10}}{{24}} = \dfrac{1}{{24}}\end{array}\
a) \(\dfrac{-1}{13}+\dfrac{9}{13}=\dfrac{\left(-1\right)+9}{13}=\dfrac{8}{13}\)
b) \(\dfrac{-3}{8}+\dfrac{5}{12}=\dfrac{-9}{24}+\dfrac{10}{24}=\dfrac{\left(-9\right)+10}{24}=\dfrac{1}{24}\)
a: =35/11-13/11-7/13-6/13
=2-1=1
b: =2+1/7+6/7+7/9-25/9
=2+1-2=1
c: \(=\dfrac{132}{321}\left(-\dfrac{103}{13}-\dfrac{27}{13}\right)=\dfrac{-132}{321}\cdot10=-\dfrac{440}{107}\)
2:
a: \(2^2\cdot3-4=4\cdot3-4=12-4=8\)
b: \(16-2^3\cdot2=16-2^4=16-16=0\)
c: \(4^2-4\cdot2=16-8=8\)
d: \(3^3-2\cdot3^2=27-2\cdot9=27-18=9\)
e: \(7^2-9\cdot2^2=49-9\cdot4=49-36=13\)
f: \(2^2\cdot3+4^2=4\cdot3+16=12+16=28\)
Bài 1:
a: \(13+21\cdot5-\left(198:11-8\right)\)
\(=13+105-18+8\)
=21+87
=108
b: \(272:16-5+4\cdot\left(30-5-255:17\right)\)
\(=17-5+4\cdot\left(30-5-15\right)\)
\(=12+4\cdot10=12+40=52\)
c: \(15\cdot24-14\cdot5\cdot\left(145:5-27\right)\)
\(=360-70\left(29-27\right)\)
=360-140
=220
d: \(18\cdot3-18\cdot2+3\cdot\left(\dfrac{51}{17}\right)\)
\(=18\left(3-2\right)+3\cdot3\)
=18+9
=27
e: \(64+115+36-25\cdot8\cdot6\cdot2^2\cdot3+4^2\)
\(=100+115-200\cdot6\cdot4\cdot3+16\)
\(=231-14400=-14169\)
f: \(15\cdot8-\left(17-30+83\right)-144:6\)
\(=120-24-\left(100-30\right)\)
=96-70
=26
\(\dfrac{3}{5}+\dfrac{13}{25}-\dfrac{5}{9}-\dfrac{3}{7}\)
\(=\dfrac{15}{25}+\dfrac{13}{25}-\dfrac{35}{63}-\dfrac{27}{63}\)
\(=\dfrac{28}{25}-\dfrac{62}{63}=\dfrac{214}{1575}\)
a: Ta có: \(\left(8\cdot5^7+5^6-5^5\right):5^5\)
\(=8\cdot5^2+5-1\)
\(=200+4=204\)
b: Ta có: \(\left(9^{30}-27^{19}\right):3^{57}+\left(125^9-25^{12}\right):5^{24}\)
\(=3^{60}:3^{57}-3^{57}:3^{57}+5^{27}:5^{24}-5^{24}:5^{24}\)
\(=27-1+125-1\)
=150
a. (8,57 - 55 + 56) : 55
= (8,57 : 55) - (55 : 55) + (56 : 55)
= 1,72 - 1 + 5
= 2,89 - 1 + 5
= 6,89
b. (930 - 2719) : 357 + (1259 - 2512) : 524
= (930 : 357) - (2719 : 357) + (1259 : 524) - (2512 : 524)
= 33 - 1 + 125 - 1
= 27 - 1 + 125 - 1
= 150
c. (1012 + 511 . 29 - 513 - 28) : 4 . 55 . 106
= (1012 + 2,5 , 1010 - 513 - 28) : 1,25 . 1010
= (1012 : 1,25 . 1010) + (2,5 . 1010 : 1,25 . 1010) - (513 : 1,25 . 1010) - (28 : 1,25 . 1010)
= 80 + 2 - \(\dfrac{25}{256}\) - \(\dfrac{1}{48828125}\)
= 81,90234373 \(\approx\) 82
a) 25 + ( - 13 + 8 )
= 25 + (-5)
= 20
b) 7 + ( - 12 + 43 ) - [ 2 + ( 19 - 34)]
= 7 + (-12 + 43 ) - [ 2 + (-15) ]
= 7 + 31 - (-13)
= 7 + 31 + 13
= 38 + 13
= 51
Mình trước nhất mà !!!