a)$\dfrac{-12}{15} \dfrac{-4}{26}$ b)$5\dfrac{1}{3}-2\dfrac{4}{5}$c)$\dfrac{4}{5}-\left(-\dfrac{2}{7}\right) -\dfrac{5}{10}$ d)\(-1\dfrac...

#Toán lớp 7

1

NL

Nguyễn Lê Phước Thịnh

26 tháng 7 2021

a) $\dfrac{-12}{15}+\dfrac{-4}{26}=\dfrac{-4}{5}+\dfrac{-2}{13}=\dfrac{-52-10}{65}=\dfrac{-62}{65}$

b) $5\dfrac{1}{3}-2\dfrac{4}{5}=\dfrac{16}{3}-\dfrac{14}{5}=\dfrac{80}{15}-\dfrac{42}{15}=\dfrac{38}{15}$

c) $\dfrac{4}{5}-\left(-\dfrac{2}{7}\right)+\dfrac{-5}{10}=\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{1}{2}=\dfrac{56}{70}+\dfrac{20}{70}-\dfrac{35}{70}=\dfrac{41}{70}$

d) $-1\dfrac{2}{7}+\dfrac{3}{14}-\dfrac{5}{21}=\dfrac{-9}{7}+\dfrac{3}{14}-\dfrac{5}{21}=\dfrac{-54}{42}+\dfrac{9}{42}-\dfrac{10}{42}=\dfrac{-55}{42}$

e) $12-\dfrac{11}{121}+\left(\dfrac{-8}{9}\right)-\left(-\dfrac{3}{7}\right)$

$=12-\dfrac{11}{121}-\dfrac{8}{9}+\dfrac{3}{7}$

$=\dfrac{91476}{7623}-\dfrac{693}{7623}-\dfrac{6776}{7623}+\dfrac{3267}{7623}$

$=\dfrac{7934}{693}$

NH

Nhàn Hạ

20 tháng 7 2021

1, A= $\dfrac{-3}{4}.\left(0,125-1\dfrac{1}{2}\right):\dfrac{33}{16}-25\%$

2, B= $1\dfrac{13}{15}.0,75-\left(\dfrac{11}{20}+25\%\right):\dfrac{7}{3}$

3, C= $\dfrac{5}{16}:0,125-\left(2\dfrac{1}{4}-0,6\right).\dfrac{10}{11}$

4, D= $6\dfrac{5}{12}:2\dfrac{5}{4}+11\dfrac{1}{4}.\left(\dfrac{1}{3}-\dfrac{1}{5}\right)$

3

H

Ħäńᾑïě🧡♏

20 tháng 7 2021

$1,A=-\dfrac{3}{4}.\left(0,125-1\dfrac{1}{2}\right):\dfrac{33}{16}-25\%$

$A=-\dfrac{3}{4}.\left(0,125-\dfrac{3}{2}\right):\dfrac{33}{16}-\dfrac{1}{4}$

$A=-\dfrac{3}{4}.\left(-\dfrac{11}{8}\right):\dfrac{33}{16}-\dfrac{1}{4}$

$A=\dfrac{33}{32}:\dfrac{33}{16}-\dfrac{1}{4}$

$A=\dfrac{33}{32}.\dfrac{16}{33}-\dfrac{1}{4}$

$A=\dfrac{1}{2}-\dfrac{1}{4}$

$A=\dfrac{2}{4}-\dfrac{1}{4}$

$A=\dfrac{1}{4}$

Đúng(2)

NH

Nhàn Hạ

20 tháng 7 2021

Còn mấy câu kia ạ

NT

Nguyễn Thị Diệu Ly

17 tháng 4 2021

bài...

2

YC

Ye Chi-Lien

17 tháng 4 2021

ngu

Bài 1: Thực hiện phép tính a) $\left(\dfrac{3}{8}+\dfrac{-3}{4}+\dfrac{7}{12}\right):\dfrac{5}{6}+\dfrac{1}{2}$ b) $\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)$ c)...

NT

Nguyễn Thị Diệu Ly

17 tháng 4 2021

ko giải đc thì đi ra chỗ khác

Đúng(2)

NN

no no

29 tháng 3 2017

2

PN

Phạm Ngân Hà

28 tháng 4 2017

Bài 1:

a) $\left(\dfrac{3}{8}+\dfrac{-3}{4}+\dfrac{7}{12}\right):\dfrac{5}{6}+\dfrac{1}{2}$

$=\left(\dfrac{9}{24}+\dfrac{-18}{24}+\dfrac{14}{24}\right):\dfrac{5}{6}+\dfrac{1}{2}$

$=\dfrac{5}{24}:\dfrac{5}{6}+\dfrac{1}{2}$

$=\dfrac{5}{24}.\dfrac{6}{5}+\dfrac{1}{2}$

$=\dfrac{1}{4}+\dfrac{1}{2}$

$=\dfrac{1}{4}+\dfrac{2}{4}$

$=\dfrac{3}{4}$

b) $\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)$

$=\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}$

$=\left(\dfrac{1}{2}+\dfrac{4}{5}\right)+\left(\dfrac{3}{4}-\dfrac{3}{4}\right)$

$=\dfrac{1}{2}+\dfrac{4}{5}$

$=\dfrac{5}{10}+\dfrac{8}{10}$

$=\dfrac{9}{5}$

c) $6\dfrac{5}{12}:2\dfrac{3}{4}+11\dfrac{1}{4}.\left(\dfrac{1}{3}+\dfrac{1}{5}\right)$

$=\dfrac{77}{12}:\dfrac{11}{4}+\dfrac{42}{4}.\left(\dfrac{1}{3}+\dfrac{1}{5}\right)$

$=\dfrac{77}{12}.\dfrac{4}{11}+\dfrac{42}{4}.\left(\dfrac{5}{15}+\dfrac{3}{15}\right)$

$=\dfrac{7}{3}+\dfrac{42}{4}.\dfrac{8}{15}$

$=\dfrac{7}{3}+\dfrac{14.2}{1.3}$

$=\dfrac{7}{3}+\dfrac{28}{3}$

$=\dfrac{35}{3}$

d) $\left(\dfrac{7}{8}-\dfrac{3}{4}\right).1\dfrac{1}{3}-\dfrac{2}{7}.\left(3,5\right)^2$

$=\left(\dfrac{7}{8}-\dfrac{6}{8}\right).\dfrac{4}{3}-\dfrac{2}{7}.12\dfrac{1}{4}$

$=\dfrac{1}{8}.\dfrac{4}{3}-\dfrac{2}{7}.\dfrac{49}{4}$

$=\dfrac{1}{6}-\dfrac{7}{2}$

$=\dfrac{1}{6}-\dfrac{21}{6}$

$=\dfrac{-10}{3}$

e) $\left(\dfrac{3}{5}+0,415-\dfrac{3}{200}\right).2\dfrac{2}{3}.0,25$

$=\left(\dfrac{3}{5}+\dfrac{83}{200}-\dfrac{3}{200}\right).\dfrac{8}{3}.\dfrac{1}{4}$

$=\left(\dfrac{120}{200}+\dfrac{83}{200}-\dfrac{3}{200}\right).\dfrac{8}{3}.\dfrac{1}{4}$

$=1.\dfrac{8}{3}.\dfrac{1}{4}$

$=\dfrac{2}{3}$

f) $\dfrac{5}{16}:0,125-\left(2\dfrac{1}{4}-0,6\right).\dfrac{10}{11}$

$=\dfrac{5}{16}:\dfrac{1}{8}-\left(\dfrac{9}{4}-\dfrac{3}{5}\right).\dfrac{10}{11}$

$=\dfrac{5}{16}.\dfrac{8}{1}-\left(\dfrac{45}{20}-\dfrac{12}{20}\right).\dfrac{10}{11}$

$=\dfrac{5}{2}-\dfrac{33}{20}.\dfrac{10}{11}$

$=\dfrac{5}{2}-\dfrac{3}{2}$

$=\dfrac{2}{2}=1$

g) $0,25:\left(10,3-9,8\right)-\dfrac{3}{4}$

$=\dfrac{1}{4}:\dfrac{1}{2}-\dfrac{3}{4}$

$=\dfrac{1}{4}.\dfrac{2}{1}-\dfrac{3}{4}$

$=\dfrac{1}{2}-\dfrac{3}{4}$

$=\dfrac{2}{4}-\dfrac{3}{4}$

$=\dfrac{-1}{4}$

h) $1\dfrac{13}{15}.0,75-\left(\dfrac{11}{20}+20\%\right):\dfrac{7}{3}$

$=\dfrac{28}{15}.\dfrac{3}{4}-\left(\dfrac{11}{20}+\dfrac{1}{5}\right):\dfrac{7}{3}$

$=\dfrac{7}{5}-\left(\dfrac{11}{20}+\dfrac{4}{20}\right):\dfrac{7}{3}$

$=\dfrac{7}{5}-\dfrac{3}{4}:\dfrac{7}{3}$

$=\dfrac{7}{5}-\dfrac{9}{28}$

$=\dfrac{196}{140}-\dfrac{45}{140}$

$=\dfrac{151}{140}$

i) $\dfrac{\left(\dfrac{1}{2-0,75}\right).\left(0,2-\dfrac{2}{5}\right)}{\dfrac{5}{9}-1\dfrac{1}{12}}$

$=\dfrac{\left(\dfrac{1}{1,25}\right).\left(\dfrac{1}{5}-\dfrac{2}{5}\right)}{\dfrac{5}{9}-\dfrac{13}{12}}$

$=\dfrac{\dfrac{1}{1,25}.\dfrac{-1}{5}}{\dfrac{20}{36}-\dfrac{39}{36}}$

$=\dfrac{\dfrac{-1}{6,25}}{\dfrac{-19}{36}}$

k) $\dfrac{\dfrac{2}{3}+\dfrac{2}{7}-\dfrac{1}{14}}{-1-\dfrac{3}{7}+\dfrac{3}{28}}$

$=\dfrac{\dfrac{2}{3}+\dfrac{2}{7}-\dfrac{2}{28}}{-\dfrac{3}{3}-\dfrac{3}{7}+\dfrac{3}{28}}$

$=\dfrac{2\left(\dfrac{1}{3}+\dfrac{1}{7}-\dfrac{1}{28}\right)}{\left(-3\right)\left(\dfrac{1}{3}+\dfrac{1}{7}-\dfrac{1}{28}\right)}$

$=-\dfrac{2}{3}$

PN

Phạm Ngân Hà

29 tháng 4 2017

$A=0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}$

$A=\dfrac{7}{10}.\dfrac{8}{3}.20.\dfrac{3}{8}.\dfrac{5}{28}$

$A=\left(\dfrac{7}{10}.\dfrac{5}{28}\right).\left(\dfrac{8}{3}.\dfrac{3}{8}\right).20$

$A=\dfrac{1}{8}.1.20$

$A=\dfrac{20}{8}=\dfrac{5}{2}$

$B=\left(9\dfrac{30303}{80808}+7\dfrac{303030}{484848}\right)+4,03$

$B=\left(9\dfrac{3}{8}+7\dfrac{5}{8}\right)+4,03$

$B=\left[\left(9+7\right)+\left(\dfrac{3}{8}+\dfrac{5}{8}\right)\right]+4,03$

$B=\left(16+1\right)+4,03$

$B=17+4,03$

$B=21,03$

$C=\left(9,75.21\dfrac{3}{7}+\dfrac{39}{4}.18\dfrac{4}{7}\right).\dfrac{15}{78}$

$C=\left(\dfrac{39}{4}.\dfrac{150}{7}+\dfrac{39}{4}.\dfrac{130}{7}\right).\dfrac{15}{78}$

$C=\dfrac{39}{4}.\left(\dfrac{150}{7}+\dfrac{130}{7}\right).\dfrac{15}{78}$

$C=\dfrac{39}{4}.40.\dfrac{15}{78}$

$C=390.\dfrac{15}{78}$

$C=75$

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

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

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

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

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

$=0=0$

NH

Nguyễn Hoàng Gia Bảo

5 tháng 5 2021

Tính:

a) $\dfrac{-5}{6}+\dfrac{1}{6}$

b) $\dfrac{1}{3}-\dfrac{5}{4}.\dfrac{4}{15}$

c) $4.\left(-5\right)^2+\left(-2\right)^3.25$

d) $\dfrac{-2}{7}+\dfrac{1}{5}:\dfrac{7}{15}$

4

LN

Lê Ngọc Anh

5 tháng 5 2021

a) $\dfrac{-4}{6}$

b) $\dfrac{1}{3}$-$\dfrac{20}{60}$

= 0

c) $-20^2$+($-50^3$)

= -400 + (-125000)

=-125400

d) $\dfrac{-2}{7}$+$\dfrac{15}{35}$

= $\dfrac{-10}{35}$+$\dfrac{15}{35}$

= $\dfrac{5}{35}$=$\dfrac{1}{7}$

Đúng(1)

LN

Lê Ngọc Anh

5 tháng 5 2021

Nhớ tick cho mk nha

NS

Nhi Sieu Quay

3 tháng 11 2018

...

#Toán lớp 7

2

NN

Nguyễn Ngọc Linh

3 tháng 11 2018

f, $\dfrac{2^9.4^{10}}{8^8}=\dfrac{2^9.\left(2^2\right)^{10}}{\left(2^3\right)^8}=\dfrac{2^9.2^{20}}{2^{24}}=\dfrac{2^{29}}{2^{24}}=2^5=32$

NL

Nguyễn Lê Phước Thịnh

16 tháng 11 2022

a: $=\left(\dfrac{1}{3}-\dfrac{4}{3}\right)+\dfrac{14}{25}+\dfrac{11}{25}+\dfrac{2}{7}=\dfrac{2}{7}$

b: $=\dfrac{3}{7}-\dfrac{5}{2}-\dfrac{3}{5}+\dfrac{4}{7}+\dfrac{3}{2}-\dfrac{2}{5}=1-1-1=-1$

c: $=\dfrac{4}{25}+\dfrac{7}{5}\cdot\dfrac{5}{2}-2=\dfrac{4}{25}+\dfrac{7}{2}-2=\dfrac{83}{50}$

bài 1: tính a) $\dfrac{5^4.20^4}{25^5.4^5}$ b)3,5-$\left(-\dfrac{2}{7}\right)$ c)$\left(\dfrac{11}{12}:\dfrac{33}{16}\right).\dfrac{3}{5}$ d)$15.\left(-\dfrac{2}{3}\right)^2.-\dfrac{7}{3}$ e)$\left(\dfrac{9}{25}-2.8\right):\left(3\dfrac{4}{5}+0,2\right)$ g)$\dfrac{21}{47}+\dfrac{9}{45}+\dfrac{26}{47}+\dfrac{4}{5}$ h)$\dfrac{15}{12}+\dfrac{5}{13}-\dfrac{3}{12}-\dfrac{18}{13}$ j)12.$\left(-\dfrac{2}{3}\right)^2+\dfrac{4}{3}$...

NT

Nguyễn Tăng Nhật Trường

6 tháng 12 2018

#Toán lớp 7

2

CE

Chitanda Eru (Khối kiến thức)

6 tháng 12 2018

Toàn câu dễ nên bạn tự làm đi.

Trong lúc bạn đánh xong bài này thì bạn có thể làm xong rồi đó.

Đừng có ỷ lại vào người khác ,động não lên.

NT

Nguyễn Tăng Nhật Trường

6 tháng 12 2018

ok

Tính giá trị biểu thứca, $19\dfrac{5}{8}:\dfrac{7}{12}-15\dfrac{1}{4}:\dfrac{7}{12}$ b,$\dfrac{2}{5}.\dfrac{1}{3}-\dfrac{2}{15}:\dfrac{1}{5}+\dfrac{3}{5}.\dfrac{1}{3}$c, $\left(3\dfrac{1}{3}+2,5\right):\left(3\dfrac{1}{6}-4\dfrac{1}{5}\right)-\dfrac{11}{31}$ d, $\left[6+\left(\dfrac{1}{2}\right)^3-\left|-\dfrac{1}{2}\right|\right]:\dfrac{3}{12}$ ...

KJ

❖ Khang/GD❄ 『ʈєɑɱ❖Hoàng๖ۣۜGia☆』

27 tháng 1 2022

3

R

Rhider

27 tháng 1 2022

a) $=\dfrac{157}{8}.\dfrac{12}{7}-\dfrac{61}{4}.\dfrac{12}{7}=\dfrac{12}{7}\left(\dfrac{157}{8}-\dfrac{61}{4}\right)=\dfrac{12}{7}.\dfrac{35}{8}=\dfrac{15}{2}$

b) $\dfrac{2}{5}.\dfrac{1}{3}-\dfrac{2}{15}\div\dfrac{1}{5}+\dfrac{3}{5}.\dfrac{1}{3}=\dfrac{1}{3}\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{2}{15}.5=\dfrac{1}{3}.1-\dfrac{2}{3}=\dfrac{1}{3}-\dfrac{2}{3}=-\dfrac{1}{3}$

c) $=-\dfrac{80}{9}$

Đúng(3)

R

Rhider

27 tháng 1 2022

d) $=-\dfrac{1}{6}$

Đúng(1)

PL

Phạm Lê Bảo Châu

21 tháng 4 2022

Câu 1: Thực hiện phép tính
a, $\dfrac{7}{9}-\dfrac{16}{9}$

b, $\dfrac{2}{-15}+\dfrac{7}{10}$

c, $\left(4\dfrac{2}{3}-4\dfrac{3}{4}\right):\dfrac{-5}{12}-\dfrac{4}{5}$

d, $\dfrac{-141}{157}.\dfrac{23}{59}-\dfrac{141}{157}.\dfrac{36}{59}+\dfrac{16}{-157}$

1

N

NguyetThienn

21 tháng 4 2022

a. 7/9 - 16/9 = -9/9 = -1

b. 2/-15 + 7/10 = 17/30

c. (4 2/3 - 4 3/4) : -5/12 - 4/5

= (14/3 - 19/4) : (-5/12) - 4/5

= -1/12 : (-5/12) - 4/5

= 1/5 - 4/5

= -3/5

Đúng(1)

PL

Phạm Lê Bảo Châu

21 tháng 4 2022

thanks