Tính bằng cách hợp lí:a) $\frac{15}{12} \frac{5}{13}-\frac{3}{12}-\frac{18}{13}$ ( Phép này tính bằng 1 nhưng lại sai mất)b) $\frac{13}{25} \frac{6}{41}-\frac{38}{25} \frac{35}{41}-\frac{1}{2}$c) ...

1

LM

Lương Minh Tuấn

19 tháng 12 2018

$a,=\left(\frac{15}{12}-\frac{3}{12}\right)+\left(\frac{5}{13}-\frac{18}{13}\right)$

$=1+-1$

$=0$

NT

nguyễn thị oanh

12 tháng 12 2019

Thực hiện phép tính ( tính hợp lí nếu có thể )

a)$\frac{1}{5}+\frac{-2}{3}$

b)$\frac{15}{12}+\frac{5}{13}-\frac{3}{12}-\frac{18}{13}$

c) $\frac{13}{25}+\frac{6}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}$

d)$\frac{5}{6}.18\frac{2}{3}-\frac{5}{6}.6\frac{2}{3}$

Mấy bạn làm được câu nào thì làm nha! THANKS

3

D

阮草~๖ۣۜDαɾƙ

12 tháng 12 2019

$a.=\frac{3}{15}+\frac{-10}{15}$

$=-\frac{7}{15}$

$b.=\left(\frac{15}{12}-\frac{3}{12}\right)+\left(\frac{5}{13}-\frac{18}{13}\right)$

$=1+\left(-1\right)$

$=0$

D

阮草~๖ۣۜDαɾƙ

12 tháng 12 2019

$c.=\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}$

$=-1+1-\frac{1}{2}$

$=0-\frac{1}{2}$

$=-\frac{1}{2}$

$d.=\frac{5}{6}.\left(18\frac{2}{3}-6\frac{2}{3}\right)$

$=\frac{5}{6}.12$

$=10$

LN

le nguyen hien anh

11 tháng 12 2019

...

3

HT

Hoàng Thanh Huyền

11 tháng 12 2019

a) $\frac{15}{12}+\frac{5}{13}-\frac{3}{12}-\frac{18}{13}=\left(\frac{15}{12}-\frac{3}{12}\right)+\left(\frac{5}{13}-\frac{18}{13}\right)$

$=1+\left(-1\right)$

$=0$

b) $\frac{11}{24}-\frac{5}{41}+\frac{13}{24}+0,5-\frac{36}{41}=\left(\frac{11}{24}+\frac{13}{24}\right)+\left(-\frac{5}{41}-\frac{36}{41}\right)+0,5$

$=1+\left(-1\right)+0,5$

$=0,5$

_Học tốt nha_

LT

Lê Trần Khánh Linh

11 tháng 12 2019

a, $\frac{15}{12}$+ $\frac{5}{13}$- $\frac{3}{12}$-$\frac{18}{13}$

= $\frac{5}{4}$+ $\frac{5}{13}$ - $\frac{1}{4}$ - $\frac{18}{13}$

= $\left(\frac{5}{4}-\frac{1}{4}\right)$+ $\left(\frac{5}{13}-\frac{18}{13}\right)$

= 1 - 1 = 0

b, $\frac{11}{24}$- $\frac{5}{41}$+ $\frac{13}{24}$+ 0,5 - $\frac{36}{41}$

= $\left(\frac{11}{24}+\frac{13}{24}\right)$- $\left(\frac{5}{41}+\frac{36}{41}\right)$+ 0,5

= 1 - 1 + 0,5 = 0,5

c, $\left(-\frac{3}{4}+\frac{2}{3}\right):\frac{5}{11}+\left(-\frac{1}{4}+\frac{1}{3}\right):\frac{5}{11}$

=$\left(-\frac{3}{4}+\frac{2}{3}\right).\frac{11}{5}+\left(-\frac{1}{4}+\frac{1}{3}\right).\frac{5}{11}$

= $\frac{11}{5}.\left(-\frac{3}{4}+\frac{2}{3}-\frac{1}{4}+\frac{1}{3}\right)$

= $\frac{11}{5}.\left[\left(-\frac{3}{4}-\frac{1}{4}\right)+\left(\frac{2}{3}+\frac{1}{3}\right)\right]$

= $\frac{11}{5}.\left[\left(-1\right)+1\right]$

= 0

d, $\left(-3\right)^2.\left(\frac{3}{4}-0,25\right)-\left(3\frac{1}{2}-1\frac{1}{2}\right)$

= $9.\left(0,75-0,25\right)-2$

= 9. 0,5 - 2 = 2,5

e, $\frac{13}{25}+\frac{6}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}$

= $\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}$

= -1 + 1 - $\frac{1}{2}$

= $-\frac{1}{2}$

a) $\frac{21}{47}+\frac{9}{45}+\frac{26}{45}+\frac{4}{5}$ ; b) $\frac{15}{12}+\frac{5}{13}-\frac{3}{12}-\frac{18}{13}$c) $\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+\frac{6}{21}+\frac{1}{2}$ ; ...

TN

Tatsuno Nizaburo

7 tháng 12 2015

0

LH

Lê Hoàng Tiến Đạt

12 tháng 3 2018

Tính :

a) $\frac{2}{3}+\frac{1}{5}-\frac{10}{7}$ b)$\frac{7}{12}-\frac{27}{18}.\frac{1}{18}$

c) $\left(\frac{23}{41}-\frac{15}{82}\right).\frac{41}{25}$

d) $\left(\frac{4}{5}+\frac{1}{2}\right).\left(\frac{3}{13}-\frac{8}{13}\right)$

2

ID

I don't need you

12 tháng 3 2018

A) $\frac{2}{3}+\frac{1}{5}-\frac{10}{7}=\frac{13}{15}-\frac{10}{7}=\frac{-59}{105}$

B) $\frac{7}{12}-\frac{27}{18}.\frac{2}{18}=\frac{7}{12}-\frac{3}{2}.\frac{2}{18}=\frac{7}{12}-\frac{1}{6}=\frac{5}{12}$

C) $\left(\frac{23}{41}-\frac{15}{82}\right).\frac{41}{25}=\frac{31}{82}.\frac{41}{25}=\frac{31}{50}$

D) $\left(\frac{4}{5}+\frac{1}{2}\right).\left(\frac{3}{13}-\frac{8}{13}\right)=\frac{13}{10}.\frac{-5}{13}=\frac{-1}{2}$

DD

Đình Danh Nguyễn

12 tháng 3 2018

a, = $\frac{-59}{105}$

b = $\frac{7}{144}$

c= $\frac{31}{50}$

d=$\frac{-1}{2}$

HL

Hỏa Long

13 tháng 5 2018

$\frac{13}{25}+\frac{6}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}$

$1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$

2

TN

truong nhat linh

13 tháng 5 2018

$\frac{13}{25}+\frac{6}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}$

$=\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}$

$=-1+1-\frac{1}{2}=0-\frac{1}{2}$

$=\frac{-1}{2}$

$1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$

$=\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5$

$=1+1+0,5=2,5$

DS

Dragon song tử

13 tháng 5 2018

$\frac{13}{25}+\frac{4}{41}-\frac{38}{25}+\frac{35}{41}-\frac{1}{2}$

= $\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}$

= $-1+1-\frac{1}{2}=-\frac{1}{2}$

$1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$

=$\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5$

= $1+1+0,5=2,5$

Bài 1: Tính bằng cách hợp lí nhất.a.$\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{2006.2007}$b.$\frac{30}{51}-\frac{20}{52}+\frac{14}{34}-\frac{56}{91}-2$c.$[\frac{1}{3}+\frac{12}{67}+\frac{13}{41}]-[\frac{79}{67}-\frac{28}{41}]$d.$\frac{2}{15}+\frac{2}{35}+\frac{2}{63}+\frac{2}{99}+...+\frac{2}{399}$Ai nhanh mik tick 3 cái, mik dg cần...

S

stayhome

14 tháng 3 2020

Bài 12 : Thực hiện phép tính một cách hợp lí:p) $\frac{-5}{9}+\frac{8}{15}+\frac{-2}{11}+\frac{4}{-9}+\frac{7}{15}$ q) $\frac{5}{13}+\frac{-5}{17}+\frac{-20}{41}+\frac{8}{13}+\frac{-21}{41}$ ...

0

TQ

Trần Quang Hiếu

26 tháng 7 2016

1

N

ncjocsnoev

26 tháng 7 2016

p) $\frac{-5}{9}+\frac{8}{15}+\frac{-2}{11}+\frac{4}{-9}+\frac{7}{15}$

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

$=-1+1+\frac{-2}{11}$

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

q) $\frac{5}{13}+\frac{-5}{17}+\frac{-20}{41}+\frac{8}{13}+\frac{-21}{41}$

$=\left(\frac{5}{13}+\frac{8}{13}\right)+\left(\frac{-20}{41}+\frac{-21}{41}\right)+\frac{-5}{17}$

$=1+\left(-1\right)+\frac{-5}{17}=\frac{-5}{17}$

r) $\frac{1}{5}+\frac{-2}{9}+\frac{-7}{9}+\frac{4}{5}+\frac{16}{17}$

$=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{-2}{9}+\frac{-7}{9}\right)+\frac{16}{17}$

$=1+\left(-1\right)+\frac{16}{17}=\frac{16}{17}$

TJ

The jieb

24 tháng 7 2018

1) Tính hợp...

3

R

Rinu

18 tháng 6 2019

Trả lời

b)(1/3+12/67+13/41)-(79/67-28/41)

=1/3+12/67+13/41-79/67+28/41

=1/3+(12/67-79/67)+(13/41+28/41)

=1/3+(-67/67)+41/41

=1/3+(-1)+1

=1/3+0

=1/3.

R

Rinu

18 tháng 6 2019

c)38/45-(8/45-17/51-3/11)

=38/45-8/45+17/51+3/11

=30/45+1/3+3/11

=2/3+1/3+3/11

=3/3+3/11

=1+3/11

=1 3/11.

Thực hiện phép tính:a)...

VV

VỘI VÀNG QUÁ

18 tháng 12 2016

1

DT

Dương Thu Hiền

18 tháng 12 2016

a) $\frac{11}{24}-\frac{5}{41}+\frac{13}{24}+0,5-\frac{36}{41}$

= $\frac{11}{24}-\frac{5}{41}+\frac{13}{24}+\frac{1}{2}-\frac{36}{41}$

= $\frac{1}{2}-\left\{\frac{11}{24}+\frac{13}{24}\right\}-\left\{\frac{5}{41}+\frac{36}{41}\right\}$

=$\frac{1}{2}-\frac{24}{24}-\frac{41}{41}$

=$\frac{1}{2}-1-1$

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

b) $-12:\left\{\frac{3}{4}-\frac{5}{6}\right\}^2$

= $-12:\left\{\frac{9}{12}-\frac{10}{12}\right\}^2$

= $-12:\left\{\frac{-1}{12}\right\}^2$

= $-12:\frac{1}{144}$

= $-12.144$

= -1728

c) $\frac{7}{23}.\left[\left(\frac{-8}{6}\right)-\frac{45}{18}\right]$

= $\frac{7}{23}.\left[\left(\frac{-24}{18}\right)-\frac{45}{18}\right]$

= $\frac{7}{23}.\left(\frac{-23}{6}\right)$

= $\frac{-7}{6}$

d) $23\frac{1}{4}.\frac{7}{5}-13\frac{1}{4}:\frac{5}{7}$

= $23\frac{1}{4}.\frac{7}{5}-13\frac{1}{4}.\frac{7}{5}$

= $\left\{23\frac{1}{4}-13\frac{1}{4}\right\}.\frac{7}{5}$

= $10.\frac{7}{5}$

= 14

e) $(1 + 2 3 - 1 4) . (0, 8 - 3 4) 2$

= $(1+23−14).($\frac{4}{5}$−34)2$

= $\left(\frac{12}{12}+\frac{8}{12}-\frac{3}{12}\right).\left(\frac{16}{20}-\frac{15}{20}\right)^2$

= $\frac{17}{12}.\left(\frac{1}{20}\right)^2$

= $\frac{17}{20}.\frac{1}{400}$

= $\frac{17}{8000}$