Thực hiện phép tính:
a) 1/3 + -13/21 + 5/7 + 1/6 + 1/14 + -1/2
b) 1/3 + -1/4 + 1/5 + -1/6 + 1/7 + 1/6 + 1/-5 + 1/4 + 1/-3
1, Thực hiện phép tính ( tính hợp lý nếu có thể) A, -1/12+4/3 B,(-4/14-3/15)-(1/5-20/35- -1)7 C, 3/5+ -5/20+30/75+ -7/4 D, 5/6. -12/13 + 7/13 E, 2/-9 - 5/-36 - 1/4 F, 2/23 +-5/12+7/18+21/23+ -7/12
c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)
\(=\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{-1}{4}+\dfrac{-7}{4}\)
\(=1-2=-1\)
Giải:
a)-1/12+4/3=-1/12+16/12=15/12=5/4
b)(-4/14-3/15)-(1/5-20/35-(-1)).7
=-17/35-22/35.7
=-17/35-22/5
=-171/35
c)3/5+-5/20+30/75+-7/4
=3/5+-1/4+2/5+-7/4
=(3/5+2/5)+(-1/4+-7/4)
=1+-2
=-1
d)5/6.-12/14+7/13
=-5/7+7/13
=-16/91
e)2/-9-5/-36-1/4
=-1/12-1/4
=-1/3
f)2/23+-5/12+7/18+21/23+-7/12
=(2/23+21/23)+(-5/12+-7/12)+7/18
=1+-1+7/18
=7/18
(/ là phần)
Thực hiện phép tính:
a) 1/3 + (-13)/21 + 5/7 + 1/6 +1/(-5) + 1/4 + 1/(-3)
b) 1/3 + (-1)/4 + 1/5 + (-1)/6 + 1/7 + 1/6 + 1/(-5) + 1/4 + 1/(-3)
Bài 1 , thực hiện phép tính :
a, -18 : 3/5
b, 3/4 : ( -9 )
c, 13/20 - 6/7 : 10/21
d, -21/5 : ( 7/3 . 7/5 )
e, ( -2/5 + 1/4 ) : ( 1 - 2/5 )
Lời giải:
a.
$-18: \frac{3}{5}=-18.\frac{5}{3}=-30$
b.
$\frac{3}{4}:(-9)=\frac{3}{4}.\frac{-1}{9}=\frac{-1}{12}$
c.
$\frac{13}{20}-\frac{6}{7}: \frac{10}{21}=\frac{13}{20}-\frac{6}{7}.\frac{21}{10}$
$=\frac{13}{20}-\frac{9}{5}=\frac{13}{20}-\frac{36}{20}=\frac{-23}{20}$
d.
$\frac{-21}{5}: (\frac{7}{3}.\frac{7}{5})=\frac{-21}{5}: \frac{49}{15}$
$=\frac{-21}{5}.\frac{15}{49}=\frac{-9}{7}$
e.
$(\frac{-2}{5}+\frac{1}{4}): (1-\frac{2}{5})$
$=\frac{-3}{20}: \frac{3}{5}=\frac{-1}{4}$
Thực hiện phép tính:
1,-4/7 + 2/3x -9/14
2,17/13 - ( 4/13 - 11 )
3, 8 2/7 - ( 3 4/9 + 4 2/7 )
5, ( 2/3 - 1 1/2): 4/3 + 1/2
6, -5/13 + 2/5 + -8/13 + 3/5 - 3/7
7, 6/5 x 3/7 + 6/5 : 7/10 + 6/5
\(1,-\dfrac{4}{7}+\dfrac{2}{3}\times\dfrac{-9}{14}\)
\(=\dfrac{-4}{7}+\dfrac{-18}{42}\)
\(=\dfrac{-4\times6}{7\times6}+\dfrac{-18}{42}\)
\(=\dfrac{-20}{42}+\dfrac{-18}{42}\)
\(=-\dfrac{38}{42}\)
\(=-\dfrac{19}{21}\)
\(2,\dfrac{17}{13}-\left(\dfrac{4}{13}-11\right)\)
\(=\dfrac{17}{13}-\dfrac{4}{13}+11\)
\(=\dfrac{13}{13}+11\)
\(=1+11\)
\(=12\)
\(3,8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
\(=\dfrac{58}{7}-\left(\dfrac{31}{9}+\dfrac{30}{7}\right)\)
\(=\dfrac{58}{7}-\dfrac{31}{9}-\dfrac{30}{7}\)
\(=\dfrac{58}{7}-\dfrac{30}{7}-\dfrac{31}{9}\)
\(=\dfrac{28}{7}-\dfrac{31}{9}\)
\(=\dfrac{28\times9}{7\times9}-\dfrac{31\times7}{9\times7}\)
\(=\dfrac{252}{63}-\dfrac{217}{63}\)
\(=\dfrac{35}{63}\)
\(=\dfrac{5}{9}\)
\(5,\left(\dfrac{2}{3}-1\dfrac{1}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2}{3}-\dfrac{3}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2\times2}{3\times2}-\dfrac{3\times3}{2\times3}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{4}{6}-\dfrac{9}{6}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}:\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}\times\dfrac{3}{4}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1\times12}{2\times12}\)
\(=\dfrac{-15}{24}+\dfrac{12}{24}\)
\(=\dfrac{-3}{24}\)
\(=-\dfrac{1}{8}\)
\(6,\dfrac{-5}{13}+\dfrac{2}{5}+\dfrac{-8}{13}+\dfrac{3}{5}-\dfrac{3}{7}\)
\(=\left(\dfrac{-5}{13}+\dfrac{-8}{13}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{3}{7}\)
\(=\dfrac{-13}{13}+\dfrac{5}{5}-\dfrac{3}{7}\)
\(=-1+1-\dfrac{3}{7}\)
\(=-\dfrac{3}{7}\)
\(7,\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}:\dfrac{7}{10}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}\times\dfrac{10}{7}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+1\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{1\times7}{1\times7}\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{7}{7}\right)\)
\(=\dfrac{6}{5}\times\dfrac{20}{7}\)
\(=\dfrac{120}{35}\)
\(=\dfrac{24}{7}\)
Thực hiện phép tính:
a.0,3-4/9:4/3.6/5+1
b.1+2:(2/3-1/6).(-2,25)
c.[(1/4-0,5).2+8/3]:2
d.[(3/8-5/12).6+1/3].4
e.(4/5-1):3/5-2/3.0,5
f.0,8:{0,2-7.[1/6+(5/21-5/14)]}
`@` `\text {Ans}`
`\downarrow`
`a.`
\(0,3-\dfrac{4}{9}\div\dfrac{4}{3}\cdot\dfrac{6}{5}+1\)
`=`\(0,3-\dfrac{1}{3}\cdot\dfrac{6}{5}+1\)
`=`\(0,3-0,4+1\)
`= -0,1 + 1`
`= 0,9`
`b.`
\(1+2\div\left(\dfrac{2}{3}-\dfrac{1}{6}\right)\cdot\left(-2,25\right)\)
`=`\(1+2\div\dfrac{1}{2}\cdot\left(-2,25\right)\)
`=`\(1+4\cdot\left(-2,25\right)\)
`= 1+ (-9) = -8`
`c.`
\(\left[\left(\dfrac{1}{4}-0,5\right)\cdot2+\dfrac{8}{3}\right]\div2\)
`=`\(\left(-\dfrac{1}{4}\cdot2+\dfrac{8}{3}\right)\div2\)
`=`\(\left(-\dfrac{1}{2}+\dfrac{8}{3}\right)\div2\)
`=`\(\dfrac{13}{6}\div2\)
`=`\(\dfrac{13}{12}\)
`d.`
\(\left[\left(\dfrac{3}{8}-\dfrac{5}{12}\right)\cdot6+\dfrac{1}{3}\right]\cdot4\)
`=`\(\left(-\dfrac{1}{24}\cdot6+\dfrac{1}{3}\right)\cdot4\)
`=`\(\left(-\dfrac{1}{4}+\dfrac{1}{3}\right)\cdot4\)
`=`\(\dfrac{1}{12}\cdot4=\dfrac{1}{3}\)
`e.`
\(\left(\dfrac{4}{5}-1\right)\div\dfrac{3}{5}-\dfrac{2}{3}\cdot0,5\)
`=`\(-\dfrac{1}{5}\div\dfrac{3}{5}-\dfrac{1}{3}\)
`=`\(-\dfrac{1}{3}-\dfrac{1}{3}=-\dfrac{2}{3}\)
`f.`
\(0,8\div\left\{0,2-7\left[\dfrac{1}{6}+\left(\dfrac{5}{21}-\dfrac{5}{14}\right)\right]\right\}\)
`=`\(0,8\div\left[0,2-7\left(\dfrac{1}{6}-\dfrac{5}{42}\right)\right]\)
`=`\(0,8\div\left(0,2-7\cdot\dfrac{1}{21}\right)\)
`=`\(0,8\div\left(0,2-\dfrac{1}{3}\right)\)
`= 0,8 \div (-2/15)`
`=-6`
`@` `yHGiangg.`
Thực hiện phép tính( tính hợp lí nếu có thể)
1) 14.25-28/7.19+28
2)27 3/5:12/5+12 2/5:2 2/5
3) 50%.1 1/3.10.7/35.0,75
4)2/3+1/3(-4/9+5/6):7/12
5) 2^2+10^3:10-(3^2.112:8-11).2005^0
6)[(6 3/5-3 3/14).5 5/6]:[(21-1,25):2,5]
7)2/3+2/7-1/14/-1-3/7+3/28
Mk ko ghi lại đề nhé
1 = \(350-4.19+4.7\)
\(=350-4.\left(19+7\right)\)
\(=350+4.26\)
\(=350-104=246\)
2 Câu này mình vẫn chưa hiểu là bạn ghi 27 3/5 tức là 27.3/5 hay 27\(\dfrac{3}{5}\)nên mk bỏ qua nhé
3 Cái đoạn 1 1/3 y chang câu 2
4 \(=\dfrac{2}{3}+\dfrac{1}{3}.\dfrac{7}{18}.\dfrac{12}{7}\)
\(=\dfrac{2}{3}+\dfrac{7}{54}.\dfrac{12}{7}\)
\(=\dfrac{2}{3}+\dfrac{2}{9}=\dfrac{8}{9}\)
5 \(=2^2+10^2-\left[9.\left(112:8\right)-11\right].1\)
\(=4+100-\left(9.14-11\right)\)
\(=104-115\)\(=-11\)
6 Đoạn 6 3/5 y chang 2,3
7 \(=\left(\dfrac{2}{3}-1\right)+\left(\dfrac{2}{7}-\dfrac{3}{7}\right)-\left(\dfrac{1}{14}-\dfrac{3}{28}\right)\)
\(=\dfrac{-1}{3}+\dfrac{-1}{7}-\dfrac{-1}{28}\)
\(=\dfrac{-196}{588}+\dfrac{-84}{588}-\dfrac{-21}{588}\)\(=\dfrac{259}{588}\)
Làm tạm tạm thôi xl vì có 3 câu ko hiểu
ĐỀ CƯƠNG ÔN TẬP TOÁN 6 I/ PHẦN SỐ HỌC 1/ Dạng toán thực hiện phép tính – tính nhanh nếu có thể - a) - 5/7 * 2/11 - 5/7 * 9/11 + 1 5/7 b) 11 3/13 - (2 4/7 + 5 3/13) c) 2/7 * .5 * 1/4 - 2/7 * .3 * 1/4 d) 5/7 * 1/3 - 5/7 * 1/4 - 5/7 * 1/12 75\%-1 1 2 +0,5: 5 12 -( -1 2 )^ 2 e) f) 7 19 . 8 11 + 7 19 , 3 11 - 12 19 g) - 5/12 * 2/11 - 5/12 * 9/11 + 5/12 h) - 5/7 * 2/11 - 5/7 * 9/11 + 1 5/7 i) 6 7 + 5 8 :5- 3 16 .(-2)^ 2 j) 8.(-5).(-4).2 ; *) 2 3 + 1 3 .( -2 3 + 5 6 ); 2 3 k) 1) - 2/5 + (- 5/9 + 2/5) m) 17/13 - (4/13 - 11)
1. thực hiện phép tính
a.2/3 - 11/5 = 2/3 x13/5
b. (3/18 -8/13) : (4/5 +1/2)
c. 11/6 - 6/7 +1/6 + 1/3 + -8/7
ko xem dc de ban oi :/