Tính : a) $\dfrac{17}{23}.\dfrac{8}{16}.\dfrac{23}{17}.\left(-80\right).\dfrac{3}{4}$ b) $\dfrac{5}{11}.\dfrac{18}{29}-\dfrac{5}{11}.\dfrac{8}{29} \dfrac{5}{11}.\dfrac{19}{29}$ c) \(\left(\d...

2

DH

Đừng Hỏi Tên Tôi

14 tháng 3 2017

đây là tính nhanh à nếu tính bình thường thì tính may tính là ra

NT

Nguyễn Thị Lan Anh

14 tháng 3 2017

a) 17/23 . 8/16 . 23/17. (-80) . 3/4

= (17/23 . 23/17) . (8/16 . 3/4) . (-80)

= 1 . 3/8 . (-80)

= 3/8 . (-80)

= -30

b) 5/11 . 18/29 - 5/11 . 8/29 + 5/11 . 19/29

= 5/11 . (18/29 - 8/29 + 19/29)

= 5/11 . 1

= 5/11

c)(13/23 + 1313/2323 - 131313/232323).(1/3+1/4 -7/12)

= (13/23 + 1313/2323 - 131313/232323).0

= 0

d) 1²/2x2 . 2²/2x3 . 3²/3x4 . 4²/4x5 . 5²/5x6 . 6²/6x7 . 7²/7x8 . 8²/8x9 . 9²/9x10

= 1/2 . 2/3 . 3/4 . 4/5 . 5/6 . 6/7 . 7/8 . 8/9 .9/10

= 1/10

Khó nhìn quá. Bạn thông cảm nhé!

Thực hiện phép tính: a) $1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}$ b) $\dfrac{3}{7}.19\dfrac{1}{3}-\dfrac{3}{7}.33\dfrac{1}{3}$ c) $\left(15\dfrac{1}{4}+2010\right):\left(-\dfrac{5}{7}\right)-\left(25\dfrac{1}{4}+2016\right):\left(-\dfrac{5}{7}\right)$ d)...

CB

Cô Bé Yêu Đời

21 tháng 6 2017

#Toán lớp 7

1

NH

Nguyễn Hải Dương

21 tháng 6 2017

a) $1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}=\left(1\dfrac{4}{23}-\dfrac{4}{23}\right)+\left(\dfrac{5}{21}+\dfrac{16}{21}\right)+0,5=1+1+0,5=2,5$b)

$\dfrac{3}{7}.19\dfrac{1}{3}-\dfrac{7}{7}.33\dfrac{1}{3}=\dfrac{7}{3}\left(19\dfrac{1}{3}-33\dfrac{1}{3}\right)=\dfrac{7}{3}.\left(-14\right)=-\dfrac{1}{6}$

c,

$\left(15\dfrac{1}{4}+2010\right):\left(-\dfrac{5}{7}\right)-\left(25\dfrac{1}{4}+2016\right):\left(\dfrac{-5}{7}\right)=\left(15\dfrac{1}{4}+2010\right):\left(-\dfrac{7}{5}\right)-\left(25\dfrac{1}{4}+2016\right):\left(\dfrac{-7}{5}\right)$

$\left(-\dfrac{7}{5}\right)\left(15\dfrac{1}{4}+2010-25\dfrac{1}{4}-2016\right)=\left(-\dfrac{7}{5}\right)\left(-10-6\right)=22,4$

d,

$\left(2017-\dfrac{3}{7}+\dfrac{9}{11}\right)-\left(2016-\dfrac{3}{7}+\dfrac{8}{17}\right)-\left(2015+\dfrac{9}{11}-\dfrac{8}{17}\right)=2017-\dfrac{3}{7}+\dfrac{9}{11}-2016+\dfrac{3}{7}-\dfrac{8}{17}-2015-\dfrac{9}{11}+\dfrac{8}{17}$$\left(2017-2016-2015\right)+\left(-\dfrac{3}{7}+\dfrac{3}{7}\right)+\left(\dfrac{9}{11}-\dfrac{9}{11}\right)+\left(-\dfrac{8}{17}+\dfrac{8}{17}\right)=-2014$

CB

Cô Bé Yêu Đời

22 tháng 6 2017

Bạn ơi cho mình hỏi tại sao đề bài câu c là -5/7 mà bn lm -7/5

Tính:a) $\dfrac{-5}{9}$$+\dfrac{8}{15}+\dfrac{-2}{11}+\dfrac{4}{-9}+\dfrac{7}{15}$ b)$\left(\dfrac{-5}{12}+\dfrac{6}{11}\right)+\left(\dfrac{7}{17}+\dfrac{5}{11}+\dfrac{5}{12}\right)$c) A= $49\dfrac{8}{23}-\left(5\dfrac{7}{32}+14\dfrac{8}{23}\right)$d)...

QA

Quỳnh Anh Daisy

25 tháng 7 2021

3

OY

OH-YEAH^^

25 tháng 7 2021

a) $\dfrac{-5}{9}+\dfrac{8}{15}+\dfrac{-2}{11}+\dfrac{4}{-9}+\dfrac{7}{15}$

=$\left(\dfrac{-5}{9}+\dfrac{-4}{9}\right)+\left(\dfrac{8}{15}+\dfrac{7}{15}\right)+\dfrac{-2}{11}$

=$\left(-1\right)+1+\dfrac{-2}{11}$

=$\dfrac{-2}{11}$

b) $\left(\dfrac{-5}{12}+\dfrac{6}{11}\right)+\left(\dfrac{7}{17}+\dfrac{5}{11}+\dfrac{5}{12}\right)$

=$\dfrac{-5}{12}+\dfrac{6}{11}+\dfrac{7}{17}+\dfrac{5}{11}+\dfrac{5}{12}$

=$\left(\dfrac{-5}{12}+\dfrac{5}{12}\right)+\left(\dfrac{6}{11}+\dfrac{5}{11}\right)+\dfrac{7}{17}$

=$0+0+\dfrac{7}{17}$

=$\dfrac{7}{17}$

c) A= $49\dfrac{8}{23}-\left(5\dfrac{7}{32}+14\dfrac{8}{23}\right)$

A=$49\dfrac{8}{23}-5\dfrac{7}{32}-14\dfrac{8}{23}$

A=$\left(49\dfrac{8}{23}-14\dfrac{8}{23}\right)-5\dfrac{7}{32}$

A=$35-5\dfrac{7}{32}$

A=$35-\dfrac{167}{32}=\dfrac{953}{32}$

d) C=$\dfrac{-3}{7}.\dfrac{5}{9}+\dfrac{4}{9}.\dfrac{-3}{7}+2\dfrac{3}{7}$

C=$\dfrac{-3}{7}.\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\dfrac{17}{7}$

C=$\dfrac{-3}{7}.1+\dfrac{17}{7}$

C=$\dfrac{-3}{7}+\dfrac{17}{7}=2$

Đúng(2)

HD

Hải Đức

25 tháng 7 2021

a, `(-5)/9+8/15+(-2)/11+4/(-9)+7/15`

`=-5/9+8/15-2/11-4/9+7/15`

`=(-5/9-4/9)+(8/15+7/15)-2/11`

`=-9/9+15/15-2/11`

`=-1+1-2/11`

`=-2/11`

b, `((-5)/12+6/11)+(7/17+5/11+5/12)`

`=-5/12+6/11+7/17+5/11+5/12`

`=(-5/12+5/12)+(6/11+5/11)+7/17`

`=0+11/11+7/17`

`=1+7/17`

`=17/17+7/17`

`=24/17`

c, `A=49 8/23 - (5 7/32 + 14 8/23)`

`A=49 8/23 - 5 7/32 - 14 8/23`

`A=(49 8/23 - 14 8/23)-5 7/32`

`A=35 - 167/32`

`A=953/32`

d, `C=(-3)/7.5/9+4/9.(-3)/7+2 3/7`

`C=-3/7 . 5/9-4/9 . 3/7+17/7`

`C=-3/7.(5/9+4/9)+17/7`

`C=-3/7 . 1+17/7`

`C=2`

Đúng(1)

H

huongff2k3

20 tháng 7 2021

tính
a)$\dfrac{-10}{11}.\dfrac{8}{9}+\dfrac{7}{18}.\dfrac{10}{11}$
b)$\dfrac{3}{14}:\dfrac{1}{28}-\dfrac{13}{21}:\dfrac{1}{28}+\dfrac{29}{42}:\dfrac{1}{28}-8$
c)$-1\dfrac{5}{7}.15+\dfrac{2}{7}\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)$

7

NV

Ngo VIP PRO

20 tháng 7 2021

trẻ trâu lửa chùa

hahahaha

H

huongff2k3

20 tháng 7 2021

địt mẹ mày mày bảo cái j đấy

Tìm các số nguyên dương x biết:a)$\dfrac{19}{-23}$$< \dfrac{-19}{x}$$ \dfrac{19}{-29}$ b)$\dfrac{2}{3}$$ \dfrac{88}{x}$$ \dfrac{11}{16}$ c)$\dfrac{4}{x}$$ \dfrac{x}{8}$\(...

TH

Thanh Hà Đỗ

4 tháng 2 2023

a.,$\dfrac{4}{5}+5\dfrac{1}{2}\text{x }\left(4,5-2\right)=\dfrac{7}{10}$ b,125%x$\dfrac{17}{4}:\left(1\dfrac{5}{16}-0,5\right)+2008$c,$\dfrac{5}{11}+\left(\dfrac{16}{11}+1\right)$ ...

1

NL

Nguyễn Lê Phước Thịnh

4 tháng 2 2023

a: =>19/23>19/x>19/29

=>$x\in\left\{24;25;26;27;28\right\}$

b: =>88/132<88/x<88/128

=>132>x>128

=>$x\in\left\{131;130;129\right\}$

c: =>$\left\{{}\begin{matrix}\dfrac{4}{x}-\dfrac{x}{8}< 0\\\dfrac{x}{8}-\dfrac{5}{x}< 0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{32-x^2}{8x}< 0\\\dfrac{x^2-40}{8x}< 0\end{matrix}\right.$

=>32<x^2<40

=>x=6

Đúng(1)

M

mtruc.owo

24 tháng 6 2021

#Toán lớp 5

2

Y

Yeutoanhoc

24 tháng 6 2021

`a)4/5+5 1/2 xx (4,5-2)+7/10`

`=4/5+11/2*2,5+7/10`

`=0,8+2,2+0,7`

`=3+0,7=3,7`

`b)125%xx 17/4:(1 5/16-0,5)+2008`

`=1,25xx4,25:13/16+2008`

`=85/13+2008`

`=2014 7/13`

`c)5/11+(16/11+1)`

`=5/11+1+5/11+1`

`=2+10/11=32/11`

`d)3/17+11/4+5/8+14/17+3/8`

`=3/17+14/17+5/8+3/8+11/4`

`=1+1+11/4`

`=19/4`

Đúng(3)

D

๖ۣۜDũ๖ۣۜN๖ۣۜG

24 tháng 6 2021

a)

$\dfrac{4}{5}+5\dfrac{1}{2}x\left(4,5-2\right)=\dfrac{7}{10}$

<=> $\dfrac{11}{2}x\times2,5=\dfrac{7}{10}-\dfrac{4}{5}=\dfrac{-1}{10}$

<=> $\dfrac{55}{4}x=\dfrac{-1}{10}< =>x=\dfrac{-2}{275}$

b) $125\%\times\dfrac{17}{4}:\left(1\dfrac{5}{16}-0,5\right)+2008$

= $\dfrac{85}{16}:\left(\dfrac{21}{16}-\dfrac{1}{2}\right)+2008=\dfrac{85}{16}:\dfrac{13}{16}+2008=\dfrac{26189}{13}$

c) $\dfrac{5}{11}+\left(\dfrac{16}{11}+1\right)$

= $\dfrac{21}{11}+1=\dfrac{32}{11}$

d) $\left(\dfrac{3}{17}+\dfrac{14}{17}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)+\dfrac{11}{4}$

= 1 + 1 + $\dfrac{11}{4}$ = $\dfrac{19}{4}$

Tính a, 4$\times\left(-\dfrac{1}{2}\right)^3-2\times\left(-\dfrac{1}{2}\right)^2+3\times\left(-\dfrac{1}{2}\right)+1$ b, $\dfrac{4^6\times9^5+6^9\times120}{-8^4\times3^{12}+6^{11}}$ c, $\dfrac{155-\dfrac{10}{7}-\dfrac{5}{11}+\dfrac{5}{23}}{403-\dfrac{26}{7}-\dfrac{13}{11}+\dfrac{12}{23}}+\dfrac{\dfrac{3}{5}+\dfrac{3}{13}-0,9}{\dfrac{7}{91}+0,2-\dfrac{3}{10}}$ d,$\dfrac{30\times4^7\times3^{29}-5\times14^5\times2^{12}}{54\times6^{14}\times9^7-12\times8^5\times7^5}$ ...

TT

Trịnh Thị Thảo Nhi

26 tháng 7 2017

2

KL

Khánh Linh

26 tháng 7 2017

a, $4\times\left(-\dfrac{1}{2}\right)^3-2\times\left(-\dfrac{1}{2}\right)^2+3\times\left(-\dfrac{1}{2}\right)+1$

$=\left(-\dfrac{1}{2}\right)\left[\left(4\times-\dfrac{1}{2}\right)-\left(2\times-\dfrac{1}{2}\right)+3\right]+1$

$=\left(-\dfrac{1}{2}\right)\left(-2+1+3\right)+1$

$=\left(-\dfrac{1}{2}\right)2+1$

$=-1+1$

$=0$

@Trịnh Thị Thảo Nhi

C

chugialinh

29 tháng 4 2018

a, $4\times(-12)3-2\times(-12)2+3\times(-12)+14\times(-12)3-2\times(-12)2+3\times(-12)+1$

$=(-12)[(4\times-12)-(2\times-12)+3]+1=(-12)[(4\times-12)-(2\times-12)+3]+1$

$=(-12)(-2+1+3)+1=(-12)(-2+1+3)+1$

$=(-12)2+1=(-12)2+1$

$=-1+1=-1+1$

$=0=0$

NA

Ngoc Anh Thai

Giáo viên

9 tháng 5 2021

Tính:

a) $\dfrac{17}{8}:\left(\dfrac{27}{8}+\dfrac{11}{2}\right);$

b) $\dfrac{28}{15}\cdot\dfrac{1}{4^2}.3+\left(\dfrac{8}{15}-\dfrac{69}{60}\cdot\dfrac{5}{23}\right):\dfrac{51}{54}.$

2

QN

Quang Nhân

9 tháng 5 2021

$a.$

$\dfrac{17}{8}:\left(\dfrac{27}{8}+\dfrac{11}{2}\right)$

$=\dfrac{17}{8}:\left(\dfrac{27+44}{8}\right)=\dfrac{17}{8}:\dfrac{71}{8}=\dfrac{17}{8}\cdot\dfrac{8}{71}=\dfrac{17}{71}$

$b.$

$\dfrac{28}{15}\cdot\dfrac{1}{4^2}\cdot3+\left(\dfrac{8}{15}-\dfrac{69}{60}\cdot\dfrac{5}{23}\right):\dfrac{51}{54}$

$=\dfrac{28}{15}\cdot\dfrac{1}{4^2}\cdot3+\left(\dfrac{8}{15}-\dfrac{1}{4}\right):\dfrac{51}{54}$

$=\dfrac{28}{15}\cdot\dfrac{1}{4^2}\cdot3+\left(\dfrac{8\cdot4-15}{60}\right):\dfrac{51}{54}$

$=\dfrac{28}{15}\cdot\dfrac{1}{4^2}\cdot3+\dfrac{17}{60}:\dfrac{51}{54}$

$=\dfrac{28}{15}\cdot\dfrac{1}{16}\cdot3+\dfrac{17}{60}\cdot\dfrac{54}{51}$

$=\dfrac{7}{20}+\dfrac{3}{10}$

$=\dfrac{7+3\cdot2}{20}=\dfrac{13}{20}$

Đúng(1)

LT

Lê thanh bảo

27 tháng 3 2023

Sai kìa phải bằng 11/20

MH

Minh Hăng Nguyen

10 tháng 5 2022

Tính:

a) $\dfrac{11}{10}+\dfrac{3}{5}:\dfrac{2}{3}$

b) $\dfrac{4}{3}$ + 5 x $\dfrac{5}{8}$

c) $\left(\dfrac{2}{5}+\dfrac{3}{7}\right)x\dfrac{25}{29}$

d) $\dfrac{1}{4}x\dfrac{5}{12}+\dfrac{5}{12}x\dfrac{4}{5}$

#Toán lớp 4

2

O

★彡✿ทợท彡★

10 tháng 5 2022

a) $\dfrac{11}{10}+\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{11}{10}+\dfrac{3}{5}\times\dfrac{3}{2}=\dfrac{11}{10}+\dfrac{9}{10}=\dfrac{20}{10}=2$

b) $\dfrac{4}{3}+5\times\dfrac{5}{8}=\dfrac{4}{3}+\dfrac{25}{8}=\dfrac{32}{24}+\dfrac{75}{24}=\dfrac{107}{24}$

c) $\left(\dfrac{2}{5}+\dfrac{3}{7}\right)\times\dfrac{25}{29}=\left(\dfrac{14}{35}+\dfrac{15}{35}\right)\times\dfrac{25}{39}=\dfrac{29}{35}\times\dfrac{25}{39}=\dfrac{145}{274}$

d) $\dfrac{1}{4}\times\dfrac{5}{12}+\dfrac{5}{12}\times\dfrac{4}{5}=\dfrac{5}{12}\times\left(\dfrac{1}{4}+\dfrac{4}{5}\right)=\dfrac{5}{12}\times\dfrac{21}{20}=\dfrac{105}{240}=\dfrac{7}{16}$

LM

Lê Michael

10 tháng 5 2022

a) $\dfrac{11}{10}+\dfrac{3}{5}x\dfrac{3}{2}=\dfrac{11}{10}+\dfrac{9}{10}=\dfrac{20}{10}=2$

b) $\dfrac{4}{3}+\dfrac{25}{8}=\dfrac{32}{24}+\dfrac{75}{24}=\dfrac{107}{24}$

c) $\dfrac{29}{35}x\dfrac{25}{29}=\dfrac{5}{7}$

$=\dfrac{5}{12}x\left(\dfrac{1}{4}+\dfrac{4}{5}\right)=\dfrac{5}{12}x\dfrac{21}{20}=\dfrac{7}{16}$