xin hiểu / là phần
a/ 3 và 1/2 - 4/5 - 8 và 1/2 -1/5 -(2021)^0
b 32^5/ 16^5 - (0.2)^100 * (5)^100 -√8181 + /-21/
c 3/2* 16/21 + 3/2 * 5/21 - (- 1/10) ^0 - /-20/
xin hiểu / là phần
a/ 3 và 1/2 - 4/5 - 8 và 1/2 -1/5 -(2021)^0
b 32^5/ 16^5 - (0.2)^100 * (5)^100 -√8181 + /-21/
c 3/2* 16/21 + 3/2 * 5/21 - (- 1/10) ^0 - /-20/
c: \(=\dfrac{3}{2}-1-21=\dfrac{3}{2}-21=\dfrac{-39}{2}\)
xin hiểu / là phần
a/ 3 và 1/2 - 4/5 - 8 và 1/2 -1/5 -(2021)^0
b 32^5/ 16^5 - (0.2)^100 * (5)^100 -√8181 + /-21/
c 3/2* 16/21 + 3/2 * 5/21 - (- 1/10) ^0 - /-20/
c: \(=\dfrac{3}{2}-21=\dfrac{-39}{2}\)
xin hiểu / là phần
a/ 3 và 1/2 - 4/5 - 8 và 1/2 -1/5 -(2021)^0
b 32^5/ 16^5 - (0.2)^100 * (5)^100 -\(\sqrt{81}\) + /-21/
c 3/2* 16/21 + 3/2 * 5/21 - (- 1/10) ^0 - /-20/
c: \(=\dfrac{3}{2}-21=-\dfrac{39}{2}\)
tính
a/ 3 và 1/2 - 4/5 - 8 và 1/2 -1/5 -(2021)^0
b/ 32^5/ 16^5 - (0.2)^100 * (5)^100 -√8181 + /-21/
c/ 3/2* 16/21 + 3/2 * 5/21 - (- 1/10) ^0 - /-20/
c: \(=\dfrac{3}{2}\cdot1-1-20=\dfrac{3}{2}-21=\dfrac{-39}{2}\)
Bài 1:Tính
a,3/2+5/4+5/8
b,4/5-3/8+2/4
c,3+6/8-5/4
d,5/6-1/2+2
e,3/5+6/11+7/13+2/5+16/11+19/13
g,75/100+18/21+29/32+1/4+3/21+13/32
Giusp mình nhé
a.\(\dfrac{27}{8}\)
b.\(\dfrac{37}{40}\)
c.\(\dfrac{5}{2}\)
d.\(\dfrac{7}{3}\)
e.5
g.\(\dfrac{53}{16}\)
Bài 1 :
a) \(\dfrac{3}{2}+\dfrac{5}{4}+\dfrac{5}{8}=\dfrac{12}{8}+\dfrac{10}{8}+\dfrac{5}{8}=\dfrac{12+10+5}{8}=\dfrac{27}{8}\)
b) \(\dfrac{4}{5}-\dfrac{3}{8}+\dfrac{2}{4}=\dfrac{32}{40}-\dfrac{15}{40}+\dfrac{20}{40}=\dfrac{32-15+20}{40}=\dfrac{37}{40}\)
c) \(3+\dfrac{6}{8}-\dfrac{5}{4}=\dfrac{3}{1}+\dfrac{6}{8}-\dfrac{5}{4}=\dfrac{24}{8}+\dfrac{6}{8}-\dfrac{10}{8}=\dfrac{20}{8}=\dfrac{5}{2}\)
d) \(\dfrac{5}{6}-\dfrac{1}{2}+2=\dfrac{5}{6}-\dfrac{1}{2}+\dfrac{2}{1}=\dfrac{5}{6}-\dfrac{3}{6}+\dfrac{12}{6}=\dfrac{14}{6}=\dfrac{7}{3}\)
e) \(\dfrac{3}{5}+\dfrac{6}{11}+\dfrac{7}{13}+\dfrac{2}{5}+\dfrac{16}{11}+\dfrac{19}{13}=\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{6}{11}+\dfrac{16}{11}\right)+\left(\dfrac{7}{13}+\dfrac{19}{13}\right)=1+2+2=5\)
g) \(\dfrac{75}{100}+\dfrac{18}{21}+\dfrac{29}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}=\dfrac{3}{4}+\dfrac{6}{7}+\dfrac{29}{32}+\dfrac{1}{4}+\dfrac{1}{7}+\dfrac{13}{32}=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{6}{7}+\dfrac{1}{7}\right)+\left(\dfrac{29}{32}+\dfrac{13}{32}\right)=1+1+\dfrac{21}{16}=2+\dfrac{21}{16}=\dfrac{53}{16}\)
a,3/2+5/4+5/8 = 12/8 + 10/8 + 5/8 = 27/8
b,4/5-3/8+2/4 = 32/40 - 15/40 + 20/40 = 37/40
c,3+6/8-5/4= 24/8 + 6/8 - 10/8 = 20/8 = 5/2
d,5/6-1/2+2 = 5/6 - 3/6 + 12/6 = 14/6 = 7/3
e,3/5+6/11+7/13+2/5+16/11+19/13 = ( 3/5+ 2/5) + ( 6/11 + 16/11) + ( 7/13 + 19/13) = 1 + 2 + 2 = 5
g,75/100+18/21+29/32+1/4+3/21+13/32 = 3/4 + 6/7 + 29/32 + 1/4 + 1/7 + 13/32= ( 3/4 + 1/4) + ( 29/32 + 13/32) + ( 6/7 + 1/7)= 1 + 21/16 + 1 = 53/16
Câu 3 : Tính nhanh :
a. C = 5 / 11 . 16 + 5 / 16 . 21 + 5 / 21 . 26 + ... + 5 / 61 . 66
b. D = 2 / 1 . 4 + 2 / 4 . 7 + 2 / 7 . 10 + ... + 2 / 97 . 100
a. \(C=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+...+\frac{1}{61}-\frac{1}{66}\)
\(=\frac{1}{11}-\frac{1}{66}=\frac{5}{66}\)
b. \(D=\frac{2}{3}.\left(\frac{3}{1.4}+\frac{4}{4.7}+...+\frac{3}{97.100}\right)\)
\(=\frac{2}{3}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{100}\right)\)
\(=\frac{2}{3}.\left(1-\frac{1}{100}\right)=\frac{2}{3}.\frac{99}{100}=\frac{33}{50}\)
\(C=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-....-\frac{1}{66}\)
\(C=\frac{1}{11}-\frac{1}{66}=\frac{5}{66}\)
\(D=\frac{2}{3}.\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-....-\frac{1}{100}\right)\)
\(D=\frac{2}{3}.\left(1-\frac{1}{100}\right)=\frac{2}{3}.\frac{99}{100}=\frac{33}{50}\)
nêu viết đề bài như thế thì nghĩ như là\(\frac{2\cdot4}{1}+\frac{2\cdot7}{4}...\)
=> hai bạn kia sai
tính nhanh
a) 1/1*2 + 1/2*3 + 1/3*4 + 1/4*5 + ......... + 1/98*99 + 1/99*100
b) 5/11*16 + 5/16*21 + 5/21*16 + .......... + 5/61*66
a)\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{98.99}+\frac{1}{99.100}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}\)
\(=1-\frac{1}{100}\)
\(=\frac{99}{100}\)
b)\(\frac{5}{11.16}+\frac{5}{16.21}+...+\frac{5}{61.66}\)
\(=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+....+\frac{1}{61}-\frac{1}{66}\)
\(=\frac{1}{11}-\frac{1}{66}\)
\(=\frac{5}{66}\)
a,\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{98.99}+\frac{1}{99.100}\)
ta có:
\(\frac{1}{1.2}=\frac{2-1}{1.2}=\frac{2}{1.2}-\frac{1}{1.2}=1-\frac{1}{2}\)
\(\frac{1}{2.3}=\frac{3-2}{2.3}=\frac{3}{2.3}-\frac{2}{2.3}=\frac{1}{2}-\frac{1}{3}\)
...
\(\frac{1}{99.100}=\frac{1}{99}-\frac{1}{100}\)
= \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)
=\(1-\frac{1}{100}=\frac{99}{100}\)
b,
\(\frac{5}{11.16}+\frac{5}{16.21}+\frac{5}{21.16}+...+\frac{5}{61.66}\)
ta có:
\(\frac{5}{11.16}=\frac{16-11}{11.16}=\frac{16}{11.16}-\frac{11}{11.16}=\frac{1}{11}-\frac{1}{16}\)
\(\frac{5}{16.21}=\frac{21-16}{16.21}=\frac{21}{16.21}-\frac{16}{16.21}=\frac{1}{16}-\frac{1}{21}\)
...
\(\frac{5}{61.66}=\frac{66-61}{61.66}=\frac{66}{61.66}-\frac{61}{61.66}=\frac{1}{61}-\frac{1}{66}\)
= \(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+...+\frac{1}{61}-\frac{1}{66}\)
=\(\frac{1}{11}-\frac{1}{66}\)=\(\frac{5}{66}\)
a) 1 và 4/23+(5/21-4/23)+16/21-1/2 b)75%-(5/2+5/3)+(-1/2) ngũ3 c)-3/4.(-55/9).8/11 d)-3/8.6/13+7/13.-3/8+ 1 và 3/8
`a)1 4/23 + ( 5/21-4/23)+16/21-1/2`
`=27/23+5/21-4/23+16/21-1/2`
`=(27/23-4/23)+(5/21+16/21)-1/2`
`=23/23+21/21-1/2`
`=1+1-1/2`
`=2-1/2`
`=4/2-1/2`
`=3/2`
___
`b)75%-(5/2+5/3)+(-1/2)^3`
`=3/4-5/2+5/3+(-1/8)`
`=(3/4-5/2-1/8)+5/3`
`=(6/8-20/8-1/8)+5/3`
`=-15/8+5/3`
`=-45/24+40/24`
`=-5/24`
___
`c)-3/4(-55/9).8/11`
`=-3/4.(-40/9)`
`=-10/3`
__
`d)-3/8 . 6/13 + 7/13 . (-3/8) + 1 3/8`
`= -3/8 . (6/13 + 7/13) + 11/8`
`= -3/8 . 13/13 + 11/8`
`= -3/8 .1 + 11/8`
`= -3/8 + 11/8`
`= 8/8`
`=1`
câu 3: rút gọn rồi quy đồng
a, 12/36 và -16/ 20 b, 21/ 105 và 35/ 150
Câu 4:
a, 3/10 + 5/10 b, [-27] . 36+ 64 . [-27] + 23 . [ -100]
c, 5/8 + 3/ 12 d, -2/17 + 3/19 + -15/ 17 + 16/19 + 5/6
mai mình thi rồi, các bạn giúp mình với
Câu 4:
d) Ta có: \(\dfrac{-2}{17}+\dfrac{3}{19}+\dfrac{-15}{17}+\dfrac{16}{19}+\dfrac{5}{6}\)
\(=\left(-\dfrac{2}{17}-\dfrac{15}{17}\right)+\left(\dfrac{3}{19}+\dfrac{16}{19}\right)+\dfrac{5}{6}\)
\(=-1+1+\dfrac{5}{6}=\dfrac{5}{6}\)