52/3+5/6<x<8-1/4
Câu 03:
Kết quả nào sau đây là đúng:
A.
52– (48 – 52)+48 = 0
B.
-52–(48–52)–48 = 0
C.
(-3) –(4- 6) = -1
D.
(-3) – (4 – 6 ) = -5
Tính nhẩm:
30 + 6 = 60 + 9 = 52 + 6 = 82 + 3 =
40 + 5 = 70 + 2 = 6 + 52= 3 + 82 =
30 + 6 = 36 60 + 9 = 69 52 + 6 = 58 82 + 3 = 85
40 + 5 = 45 70 + 2 = 72 6 + 52= 58 3 + 82 = 85
30 + 6 = 36 60 + 9 = 69 52 + 6 = 58 83 + 2 = 85 40 + 5 = 45 70 + 2 = 72 6 + 52 = 58 3 + 82 = 85
30 + 6 = 36 60 + 9 = 69 52 + 6 = 58 82 + 3 = 85
40 + 5 = 45 70 + 2 = 72 6 + 52 = 58 3 + 82 = 85
Chúc học tốt!Tính giá trị biểu thức:
a) A = -11/23.10/-13 +-11/13.3/-23-2/23
b) B = 1/1.2.3 + 1/2.3.4 + ... + 1/18.19.20
c) C = 52/1.6 + 52/6.11 + 52/11.16 +...+ 52/31.35
d) D = 1. 2 .3 + 2 .4. 6+ 4 .8 .12 + 7 .14 .21/ 1. 3. 5 + 2. 6. 10 + 4 .12 .20 + 7 .21 .35 + 3/5
GIÚP MIK VS AK!
\(B=\frac{1}{1\cdot2\cdot3}+\frac{1}{2\cdot3\cdot4}+\frac{1}{3\cdot4\cdot5}+\frac{1}{18\cdot19\cdot20}\)
\(B=\frac{1}{2}\left(\frac{2}{1\cdot2\cdot3}+\frac{2}{2\cdot3\cdot4}+\frac{2}{3\cdot4\cdot5}+\frac{2}{18\cdot19\cdot20}\right)\)
\(B=\frac{1}{2}\left(\frac{1}{1\cdot2}-\frac{1}{2\cdot3}+\frac{1}{2\cdot3}-\frac{1}{3\cdot4}+\frac{1}{3\cdot4}-\frac{1}{4\cdot5}+...+\frac{1}{18\cdot19}-\frac{1}{19\cdot20}\right)\)
\(B=\frac{1}{2}\left(\frac{1}{1\cdot2}-\frac{1}{19\cdot20}\right)\)
\(B=\frac{1}{2}\cdot\frac{189}{380}=\frac{189}{760}\)
\(C=\frac{52}{1\cdot6}+\frac{52}{6\cdot11}+\frac{52}{11\cdot16}+...+\frac{52}{31\cdot36}\)
\(C=\frac{52}{5}\left(\frac{5}{1\cdot6}+\frac{5}{6\cdot11}+\frac{5}{11\cdot16}+...+\frac{6}{31\cdot36}\right)\)
\(C=\frac{52}{5}\left(1-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+\frac{1}{11}-\frac{1}{16}+...+\frac{1}{31}-\frac{1}{36}\right)\)
\(C=\frac{52}{5}\cdot\left(1-\frac{1}{36}\right)\)
\(C=\frac{91}{9}\)
Tính:
34 + 2 + 3 = … | 56 – 4 + 6 = … | 86 – 6 + 4 = … |
64 + 3 – 5 = … | 78 – 3 – 3 = … | 52 + 0 – 2 = … |
Lời giải chi tiết:
34 + 2 + 3 = 39 | 56 – 4 + 6 = 58 | 86 – 6 + 4 = 84 |
64 + 3 – 5 = 62 | 78 – 3 – 3 = 72 | 52 + 0 – 2 = 50 |
)
Tính.
a) 5 + (-8).3
b) 4 + - 5 2
c) 1 – 2 – 3 + 4 + 5 – 6 – 7 + 8 + ... + 801 – 802 – 803 + 804
a) 5 + (-8) . 3 = 5 + (-24) = -19
b) 4 + - 5 2 = 4 + 25 = 29
c) 1 – 2 – 3 + 4 + 5 – 6 – 7 + 8 + … + 801 – 802 – 803 + 804
= (1 – 2 – 3 + 4) + (5 – 6 – 7 + 8) + … + (801 – 802 – 803 + 804)
= 0 + 0 + … + 0 = 0
Tính:
1, 3 1/2 + 4 3/5
2, 3/4 + 6 5/8
3, 5 3/8 + 9 2/7
4, 4 1/2 - 2 3/10
1: =7/2+23/5=35/10+46/10=81/10
2: =6/8+53/8=59/8
3: =43/8+65/7=821/56
Tính:
1, 3 1/2 + 4 3/5
2, 3/4 + 6 5/8
3, 5 3/8 + 9 2/7
4, 4 1/2 - 2 3/10
\(a,3\dfrac{1}{2}+4\dfrac{3}{5}=\dfrac{81}{10}\\ b,\dfrac{3}{4}+6\dfrac{5}{8}=\dfrac{59}{8}\\ 5\dfrac{3}{8}+9\dfrac{2}{7}=\dfrac{821}{56}\\ 4,4\dfrac{1}{2}-2\dfrac{3}{10}=\dfrac{11}{5}\)
Bài 3:
a.17-(5-9)+3.(-6)
b.175-(-58)+(-40)+25
c.(47-17).(-3)2-8.(-6-24)
d.138-420+(-52)-(-272)