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a. ( 23 - 21) + ( 19 - 17) + ( 15 - 13) + ( 11 - 9) + ( 7 - 5) + ( 3 - 1)
= 2 + 2 + 2 + 2 + 2 + 2
= 2 x 6
= 12
b. ( 24 - 22 ) + ( 20 - 18 ) + ( 16 - 14 ) + ( 12 - 10) + ( 8 - 6 ) + ( 4 - 2)
= 2 + 2 + 2 + 2 + 2 + 2
= 2 x 6
= 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]} =
a; \(\dfrac{9}{4}\) - \(\dfrac{-11}{4}\)
= \(\dfrac{9}{4}\) + \(\dfrac{11}{4}\)
= \(\dfrac{20}{4}\)
= 5
b; \(\dfrac{7}{8}\) - \(\dfrac{3}{-8}\) - \(\dfrac{1}{8}\)
= \(\dfrac{7}{8}\) + \(\dfrac{3}{8}\) - \(\dfrac{1}{8}\)
= \(\dfrac{7+3-1}{8}\)
= \(\dfrac{9}{8}\)
c; \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) - \(\dfrac{-1}{21}\)
= \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) + \(\dfrac{1}{21}\)
= \(\dfrac{-5-25+1}{21}\)
= \(\dfrac{-29}{21}\)
a, A= 1/5.6+1/6.7+1/7.8+...+1/24.25
=1/5-1/6+1/6-1/7+1/7-1/8+...+1/24-1/25
=1/5-1/25
=4/25
hok tốt k nha
= ( ...1 ) + (19992)999 · 1999
= (...1) + (...1)999 · 1999
= (...1 ) + (...1) · 1999
= (...1 ) + (...1999)
=(...2000 ) \(⋮10\)
b) 162001 - 82000
= ( ... 6 )2001 - ( 82 )1000
= (...6) - (...6)1000
=(...6 ) - (...6 )
= ( ...0 ) \(⋮10\)
c) 192005 + 112004
= ( 192 )1002 · 19 + (...1 )2004
= ( ... 1 )1002 · 19 + (...1)
= ( ...1 ) · 19 + (...1 )
= (...19 ) + (...1)
=( ... 20 ) \(⋮10\)
d) 175 + 244 - 1321
= (...74) · 17 + (..42 )2 - ( ...34 )5 · 13
= (...1) · 17 + ( ...6 )2 - ( ...1)5 · 13
= ( ...17 ) + (...6 ) - (...1) · 13
= (...23 ) - (..13)
= (...10 )\(⋮10\)
câu a) https://olm.vn/hoi-dap/question/228404.html
câu b)hhttps://olm.vn/hoi-dap/question/228404.html
c)https://olm.vn/hoi-dap/question/721614.html
d)https://olm.vn/hoi-dap/question/721614.html
1+2+3+4+5+6+7+8+9+10=55
11+12+13+14+15+16+17+18+19+20=155
1+2+3+4+5+6+7+8+9+10+11+12+13+14 +15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30-50-53=362
Bui Bao Ngoc oi! phan a,la (x+1)/10 hay x+(1/10)?
cac phan khac nua!
a ) 11 ; b ) − 5 7 ; c ) 5 4 + − 1 2 + − 7 8 = − 1 8 ;
d ) − 5 6 + 3 4 + − 13 15 = − 59 20 ; e ) − 6 7 + − 4 5 + ( − 1 ) = − 93 35 ; f ) 21 10