tính hợp lí:
a,(6 - 2/3 +1/2) - (5+5/3 -3/2) - ( 3 - 7/3 +5/2)
b,5/9 : (1/11 - 5/22)+ 5/9 : (1/15 - 2/3)
Bài 1: Tính
a. 5 × -7/10
b. 4/5 × -3/22
c. 4/9 + 4/3 × 16/4
d. 11/22 - 3/9 × 14/21
Bài 2: Tính hợp lý
A = 6/13 × 5/7 + 6/13 × 2/7 + 17/13
B = 11/15 × 4/11 + 11/15 × 5/11 + 11/15 × 2/11
C = ( 19/64 - 33/22 + 24/51 ) × ( 1/5 - 1/15 - 2/15 )
D = 8/13 × 7/12 + 8/13 × 5/12 - 1/12
BÀI 1
a, \(5\times\frac{-7}{10}=\frac{-35}{10}=\frac{-7}{2}\)
b, \(\frac{4}{5}\times\frac{-7}{10}=\frac{-28}{50}=\frac{-14}{25}\)
c, \(\frac{4}{9}+\frac{4}{3}\times\frac{16}{4}=\frac{4}{9}+\frac{16}{3}=\frac{52}{9}\)
d, \(\frac{11}{22}-\frac{3}{9}\times\frac{14}{21}=\frac{11}{22}-\frac{2}{9}=\frac{55}{198}=\frac{5}{18}\)
BÀI 2
\(A=\frac{6}{13}\times\frac{5}{7}+\frac{6}{13}\times\frac{2}{7}+\frac{17}{13}\)
\(A=\frac{30}{91}+\frac{12}{91}+\frac{17}{13}\)
\(A=\frac{30}{91}+\frac{12}{91}+\frac{119}{91}\)
\(A=\frac{161}{91}=\frac{23}{13}\)
\(B=\frac{11}{15}\times\frac{4}{11}+\frac{11}{15}\times\frac{5}{11}+\frac{11}{15}\times\frac{2}{11}\)
\(B=\frac{4}{15}+\frac{1}{3}+\frac{2}{15}\)
\(B=\frac{11}{15}\)
\(C=\left(\frac{19}{64}-\frac{33}{22}+\frac{24}{51}\right)\times\left(\frac{1}{5}-\frac{1}{15}-\frac{2}{15}\right)\)
\(C=\frac{-797}{1088}\times0\)
\(C=0\)
\(D=\frac{8}{13}\times\frac{7}{12}+\frac{8}{13}\times\frac{5}{12}-\frac{1}{12}\)
\(D=\frac{14}{39}+\frac{10}{39}-\frac{1}{12}\)
\(D=\frac{83}{156}\)
bạn biết câu náy không (24 + 11) . {546 - [14 . (64 - 2^{3}3) : 2]} =
Thực hiện phép tính: a,(9/10 - 15/16) X (5/12 - 11/15 - 7/20) b,(-1)3 + (-2/3)2: 2 2/3 + 5/6 c,15 X (-1/5)2 + 1/5 - 2 X (-1/2)3 - 1/2 d,22 - (-5/7) + (1/3)4 X 36
a, (\(\dfrac{9}{10}\) - \(\dfrac{15}{16}\)) \(\times\) ( \(\dfrac{5}{12}\) - \(\dfrac{11}{15}\) - \(\dfrac{7}{20}\))
= (\(\dfrac{72}{80}\) - \(\dfrac{75}{80}\)) \(\times\) (\(\)\(\dfrac{25}{60}\) - \(\dfrac{44}{60}\) - \(\dfrac{21}{60}\))
= - \(\dfrac{3}{80}\) \(\times\) (- \(\dfrac{2}{3}\))
= \(\dfrac{1}{40}\)
b, (-1)3 + (- \(\dfrac{2}{3}\))2 : 2\(\dfrac{2}{3}\) + \(\dfrac{5}{6}\)
= -13 + \(\dfrac{4}{9}\) : \(\dfrac{8}{3}\) + \(\dfrac{5}{6}\)
= -1 + \(\dfrac{4}{9}\) \(\times\) \(\dfrac{3}{8}\) + \(\dfrac{5}{6}\)
= -1 + \(\dfrac{1}{6}\) + \(\dfrac{5}{6}\)
= -1 + 1
= 0
c, 15 \(\times\) (- \(\dfrac{1}{5}\))2 + \(\dfrac{1}{5}\) - 2 \(\times\) (- \(\dfrac{1}{2}\))3 - \(\dfrac{1}{2}\)
= 15 \(\times\) \(\dfrac{1}{25}\) + \(\dfrac{1}{5}\) - 2 \(\times\) (- \(\dfrac{1}{8}\)) - \(\dfrac{1}{2}\)
= \(\dfrac{3}{5}\) + \(\dfrac{1}{5}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{2}\)
= \(\dfrac{4}{5}\) - \(\dfrac{1}{4}\)
= \(\dfrac{11}{20}\)
Tính
a , (-2/3 + 3/7 ) : 4/5 + (-1/3 + 4/7) : 4/5
b, 5/9: ( 1/11 - 5/22 ) + 5/9 : (1/15 - 2/3 )
a. (-2/3+3/7):4/5+(-1/3+4/7):4/5
= -5/21.5/4+5/21.5/4
= (-5/21+5/21).5/4
= 0.5/4
= 0
b. 5/9 : (1/11-5/22) + 5/9 : (1/15-2/3)
= 5/9 : (-3/22)+5/9:(-3/5)
= 5/9 . (-22/3)+5/9.(-5/3)
= 5/9.(-22/3-5/3)
= 5/9.-9
= -5
1.Tính
a) ( -2/3 + 3/7 ) : 4/5 + ( -1/3 + 4/7 ) : 4/5 = ?
b) 5/9 ( 1/11 -5/22 ) + 5/9 ( 1/15 - 2/3 )
a) \(\left(-\frac{2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(-\frac{1}{3}+\frac{4}{7}\right):\frac{4}{5}\)
\(=\left[\left(-\frac{2}{3}+\frac{3}{7}\right)+\left(-\frac{1}{3}+\frac{4}{7}\right)\right]:\frac{4}{5}\)
\(=\left[\left(-\frac{2}{3}-\frac{1}{3}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)\right]:\frac{4}{5}\)
\(=0:\frac{4}{5}\)
\(=0\)
b) \(\frac{5}{9}\left(\frac{1}{11}-\frac{5}{22}\right)+\frac{5}{9}\left(\frac{1}{15}-\frac{2}{3}\right)\)
\(=\frac{5}{9}\left[\left(\frac{2}{22}-\frac{5}{22}\right)+\left(\frac{1}{15}-\frac{10}{15}\right)\right]\)
\(=\frac{5}{9}\left[-\frac{3}{22}+\left(-\frac{3}{5}\right)\right]\)
\(=\frac{5}{9}\left(-\frac{81}{110}\right)\)
\(=-\frac{9}{22}\)
a) [(-2/3)+3/7+(-1/3)+4/7] : 4/5 =0:4/5=0
b) 5/9 (1/11-5/22+1/15-2/3)=5/9x(-81/110)=-9/22
tính một cách hợp lí:
a) \(\dfrac{-5}{18}+\dfrac{32}{45}-\dfrac{9}{10}\)
b) \(\left(\dfrac{-1}{4}+\dfrac{51}{33}-\dfrac{5}{3}\right)-\left(\dfrac{-15}{12}+\dfrac{6}{11}-\dfrac{42}{29}\right)\)
c) \(1-\dfrac{1}{2}+2-\dfrac{2}{3}+3-\dfrac{3}{4}+4-\dfrac{1}{4}-3-\dfrac{1}{3}-2-\dfrac{1}{2}-1\)
giải chi tiết giúp mình nha
a) Ta có: \(\dfrac{-5}{18}+\dfrac{32}{45}-\dfrac{9}{10}\)
\(=\dfrac{-25}{90}+\dfrac{64}{90}-\dfrac{81}{90}\)
\(=\dfrac{-42}{90}=-\dfrac{7}{15}\)
b) Ta có: \(\left(-\dfrac{1}{4}+\dfrac{51}{33}-\dfrac{5}{3}\right)-\left(-\dfrac{15}{12}+\dfrac{6}{11}-\dfrac{42}{29}\right)\)
\(=\dfrac{-1}{4}+\dfrac{17}{11}-\dfrac{5}{3}+\dfrac{5}{4}-\dfrac{6}{11}+\dfrac{42}{29}\)
\(=\dfrac{-5}{3}+\dfrac{42}{29}\)
\(=\dfrac{-145}{87}+\dfrac{126}{87}=\dfrac{-19}{87}\)
c) Ta có: \(1-\dfrac{1}{2}+2-\dfrac{2}{3}+3-\dfrac{3}{4}+4-\dfrac{1}{4}-3-\dfrac{1}{3}-2-\dfrac{1}{2}-1\)
\(=\left(1-1\right)-\left(\dfrac{1}{2}+\dfrac{1}{2}\right)+\left(2-2\right)-\left(\dfrac{2}{3}+\dfrac{1}{3}\right)+\left(3-3\right)-\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+4\)
\(=-1-1-1+4\)
=1
a) Ta có: =−2590+6490−8190=−2590+6490−8190
(−14+5133−53)−(−1512+611−4229)(−14+5133−53)−(−1512+611−4229)
=−53+4229=−53+4229
1−12+2−23+3−34+4−14−3−13−2−12−11−12+2−23+3−34+4−14−3−13−2−12−1
Tính hợp lí
a, -2/5×4/7+-3/5×2/7+-3/5
b,5/9×14/17+1/17×5/9+2/9+5/12
c,-4/25÷11/79+15/11÷25/79
d, (2/101÷5/9+-3/7)×(6/5÷1/3)
a)\(-\dfrac{2}{5}.\dfrac{4}{7}+\dfrac{-3}{5}.\dfrac{2}{7}+\dfrac{-3}{5}\)
=\(-\dfrac{2}{5}.\dfrac{4}{7}+\dfrac{3}{7}.\dfrac{-2}{5}+\dfrac{-3}{5}\)
=\(-\dfrac{2}{5}.\left(\dfrac{4}{7}+\dfrac{3}{7}\right)+\dfrac{-3}{5}\)
=\(\dfrac{-2}{5}.1+\dfrac{-3}{5}\)
=\(-\dfrac{2}{5}+\dfrac{-3}{5}\)
=\(-\dfrac{5}{5}\) = -1
\(\dfrac{5}{9}.\dfrac{14}{17}+\dfrac{1}{17}.\dfrac{5}{9}+\dfrac{2}{9}+\dfrac{5}{12}\)
=\(\dfrac{5}{9}.\left(\dfrac{14}{17}+\dfrac{1}{17}\right)+\dfrac{2}{9}+\dfrac{5}{12}\)
=\(\dfrac{5}{9}.\dfrac{15}{17}+\dfrac{2}{9}+\dfrac{5}{12}\)
=\(\dfrac{25}{51}+\dfrac{2}{9}+\dfrac{5}{12}\)
=\(\dfrac{691}{612}\)
\(-\dfrac{4}{25}:\dfrac{11}{79}+\dfrac{15}{11}:\dfrac{25}{79}\)
=\(-\dfrac{4}{25}.\dfrac{79}{11}+\dfrac{15}{11}.\dfrac{79}{25}\)
=\(-\dfrac{4}{25}.\dfrac{79}{11}+\dfrac{15}{25}.\dfrac{79}{11}\)
=\(\left(-\dfrac{4}{25}+\dfrac{15}{25}\right).\dfrac{79}{11}\)
=\(\dfrac{11}{25}.\dfrac{79}{11}\)
=\(\dfrac{79}{25}\)
Tính một cách hợp lí:
a) \(\dfrac{2}{9}+\dfrac{-3}{10}+\dfrac{-7}{10}\);
b) \(\dfrac{-11}{6}+\dfrac{2}{5}+\dfrac{-1}{6};\)
c) \(\dfrac{-5}{8}+\dfrac{12}{7}+\dfrac{13}{8}+\dfrac{2}{7}.\)
\(a.\)
\(\dfrac{2}{9}+\dfrac{-3}{10}+-\dfrac{7}{10}=\dfrac{2}{9}-1=\dfrac{2}{9}-\dfrac{9}{9}=-\dfrac{7}{9}\)
\(b.\)
\(\dfrac{-11}{6}+\dfrac{2}{5}+\dfrac{-1}{6}=\left(-\dfrac{11}{6}+-\dfrac{1}{6}\right)+\dfrac{2}{5}=-2+\dfrac{2}{5}=\dfrac{-10}{5}+\dfrac{2}{5}=\dfrac{-8}{5}\)
\(c.\)
\(-\dfrac{5}{8}+\dfrac{12}{7}+\dfrac{13}{8}+\dfrac{2}{7}=\left(-\dfrac{5}{8}+\dfrac{13}{8}\right)+\left(\dfrac{12}{7}+\dfrac{2}{7}\right)=1+2=3\)
tính:
a.(-2/3+3/7) : 4/5 + (-1/3+4/7) : 4/5
b. 5/9 : (1/11-5/22) + 5/9 : (1/15 - 2/3)
Help Me, Please !
a.(-2/3+3/7) : 4/5 + (-1/3+4/7) : 4/5
= [(-2/3 + 3/7) + (-1/3 + 4/7)] : 4/5
= [(-2/3 + (-1/3) + (3/7 + 4/7)] : 4/5
= [-1 + 1] : 4/5
= 0 : 4/5
= 0
a) \(\left(\frac{-2}{3}+\frac{3}{7}\right).\frac{5}{4}+\left(\frac{-1}{3}+\frac{4}{7}\right).\frac{5}{4}\)
=\(\left(\frac{-2}{3}+\frac{-1}{3}+\frac{3}{7}+\frac{4}{7}\right).\frac{5}{4}\)
= \(0.\frac{5}{4}=0\)
b) \(\frac{5}{9}:\left(\frac{1}{11}-\frac{5}{22}+\frac{1}{15}-\frac{2}{3}\right)\)
=\(\frac{5}{9}:\frac{-81}{110}=\frac{-550}{729}\)
Bài 4: Tìm x, biết:
a) 11 + x : 5 = 13 b) 15 + (7 – x) = 19
c) 12 + 3.(x – 5) = 30 d) 17 + (x + 4) : 3 = 21
Bài 5: Tính hợp lí:
a) 120.15 + 12.470 + 12.38.10 b) 13.58.4 + 32.26.2 + 52.10
c) 3,2.990 + 32 d) 45.(13 + 78) + 9.(87 + 22).5
e) (24 + 72 + 36 + 60) : 12
f) (2 + 4 + 6 + … + 100).(36.333 – 108.111)
1.
a.
11 + x : 5 = 13
x : 5 = 13 - 11
x : 5 = 2
x = 2 . 5
x = 10
Bài 4: Tìm x, biết:
a) 11 + x : 5 = 13
x : 5 = 2
x = 10
b) 15 + (7 – x) = 19
7 - x = 4
x = 3
c) 12 + 3.(x – 5) = 30
3 ( x - 5 ) = 18
x - 5 = 6
x = 11
d) 17 + (x + 4) : 3 = 21
( x + 4 ) : 3 = 4
x + 4 = 12
x = 8