1. Tính:
a) 25 + ( - 13 + 8 );
b) 7 + ( - 12 + 43 ) - [ 2 + ( 19 - 34)]
Tính:a) 2 + 1 . 4 b) 0,8 : [ 4 . 1,25] - [ 0,64 - 1 ] 5 7 5 25--------------------- 8 - 1 : 3 2 5 c) 8 : [ 7 - 12 ] d) ( 1,08 - 2 ) : 4 + ( 59 - 13 ). 36 9 2 7 25 7 9 4 17----------------------- [ 5 - 1 ] : 4 8 4 5
Bài 1: Thực hiện phép tính:
a/ (–4).(+125).( –25).( –8).( –6) b/ 65 – 5 ( 13 + 7)
c/ 24. ( 16 – 5) – 16. ( 24 – 5) d/ 18 . 35 – 7. 5 . 8
e/ 31 . (– 18) – 31. ( – 81) – 31
A. BÀI TẬP.
I. Số nguyên:
Bài 1: Thực hiện phép tính:
a/ (–4).(+125).( –25).( –8).( –6) b/ 65 – 5 ( 13 + 7)
c/ 24. ( 16 – 5) – 16. ( 24 – 5) d/ 18 . 35 – 7. 5 . 8
e/ 31 . (– 18) – 31. ( – 81) – 31
Bài 2: Tìm x, biết:
a/ 3x – 5 = - 7 + 65 b/ –12 + 3(–x + 7) = – 18
c/ 24: (3x – 2) = – 3
Tính:
a) \(\dfrac{{ - 1}}{{13}} + \dfrac{9}{{13}}\)
b) \(\dfrac{{ - 3}}{8} + \dfrac{5}{{12}}\)
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) \(\dfrac{-3}{8}+\dfrac{5}{12}=\dfrac{-9}{24}+\dfrac{10}{24}=\dfrac{\left(-9\right)+10}{24}=\dfrac{1}{24}\)
Dùng máy tính cầm tay để tính:
a)\(C_{25}^{13}\)
b)\(C_{30}^{25}\)
Tính:
a,35/11+(-7/13)-6/13-13/11 b,2 1/7-(-7/9)-25/9+6/7 c,132/321 x(-103/13)+(-27/13)x132/321
(Lưa ý:ở í b 2 1//7 là hỗn số)
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: \(=\dfrac{132}{321}\left(-\dfrac{103}{13}-\dfrac{27}{13}\right)=\dfrac{-132}{321}\cdot10=-\dfrac{440}{107}\)
1.Tính:
a) 13 + 21 . 5 - (198 : 11 -8)
b) 272 : 16 - 5 + 4 . (30 - 5 - 255 : 17)
c) 15 . 24 - 14 . 5 . (145 : 5 - 27)
d) 18 . 3 - 18 . 2 + 3 . (51 : 17)
e) (64 + 115 + 36) - 25 . 8 . 6 . 22 . 3 + 42
f) 15 . 8 - (17 - 30 + 83) - 144 : 6
g) 250 : 50 - (46 - 75 + 54) : 5
h) 13 . (17 - 95 + 83) - 144 : 6
i) 140 - 180 . (47 - 90 + 43) + 7
j) 24 . (15 + 30 + 85 - 120) : 10
2.Tính
a) 22 . 3 - 4 b) 16 - 23 . 2 c) 42 - 4 . 2
d) 33 - 2 . 32 e) 72 - 9 . 22 f) 22 . 3 + 42
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
Thực hiện phép tính:
a) 3/5 + 13/25 - 5/9 - 6/14
\(\dfrac{3}{5}+\dfrac{13}{25}-\dfrac{5}{9}-\dfrac{3}{7}\)
\(=\dfrac{15}{25}+\dfrac{13}{25}-\dfrac{35}{63}-\dfrac{27}{63}\)
\(=\dfrac{28}{25}-\dfrac{62}{63}=\dfrac{214}{1575}\)
Bài 1: Tìm x:a) x - 2 + 7 = 1 . 3 . -9 b) 4 . x - 1 = (-5) 5 12 2 4 16 9 2 9c) -2 . x + 5 = 7 d) 2 . x : 7 . 1 = 29 3 8 12 5 3 8 15Bài 2: Tính:a) 2 + 1 . 4 b) 0,8 : [ 4 . 1,25] - [ 0,64 - 1 ] 5 7 5 25--------------------- 8 - 1 : 3 2 5 c) 8 : [ 7 - 12 ] d) ( 1,08 - 2 ) : 4 + ( 59 - 13 ). 36 9 2 7 25 7 9 4 17----------------------- [ 5 - 1 ] : 4
Thực hiện phép tính:
a, (8.5^7 - 5^5 +5^6) : 5^5
b, (9^30 - 27^19) : 3^57 + (125^9 - 25^12) : 5^24
c, (10^12 + 5^11 . 2^9 - 5^13 - 2^8) : 4 . 5^5 . 10^6
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