(5,26+9,85)+(1,15+4,75) 

=15,11+ 5,9

=21,01

kết cho mk nha mk vừa nhanh vừa đúng

=15,11+5,90

=21,01

7,85/0,25+1,15*4+4=7,85/0,25+1,15/0,25+4

=(7,85+1,15)/0,25 +4

=9/0,25+4

=36+4

=40

\(=7,85\cdot4+1,15\cdot4+4\)

\(=\left(7,85+1,15+1\right)\cdot4\)

\(=10\cdot4=40\)

(7,85 + 1,15) / (0,25 x 4) + 4= 13

126 : 3 + 231 : 3 + 543 : 3

= ( 126 + 231 + 543 ) : 3

= 900 : 3

= 300

126 : 3 + 231 : 3 + 543 : 3

= \(126.\frac{1}{3}+231.\frac{1}{3}+543.\frac{1}{3}\)

=\(\frac{1}{3}\left(126+231+543\right)=\frac{1}{3}.900=300\)

126 : 3 + 231 : 3 + 543 : 3

= ( 126 + 231 + 543 ) : 3

= 900 : 3 = 300

P/s : Hình thức câu mới à Bonking ( -_- )

\(\frac{1}{3}\times\frac{3}{5}+\frac{1}{3}\times\frac{2}{5}\)

\(=\frac{1}{3}\times\left(\frac{3}{5}+\frac{2}{5}\right)\)

\(=\frac{1}{3}\)

cảm ơn

bang 8/5 nhe

=(12/25+13/25)+3/5

=1+3/5

=5/5+3/5

=8/5

\(\dfrac{9}{4}\times\dfrac{15}{11}+\dfrac{3}{4}:\dfrac{11}{7}-\dfrac{3}{4}\times\dfrac{8}{11}\)
\(=\dfrac{3}{4}\times3\times\dfrac{15}{11}+\dfrac{3}{4}\times\dfrac{7}{11}-\dfrac{3}{4}\times\dfrac{8}{11}\)
\(=\dfrac{3}{4}\times\dfrac{45}{11}+\dfrac{3}{4}\times\dfrac{7}{11}-\dfrac{3}{4}\times\dfrac{8}{11}\)
\(=\dfrac{3}{4}\times\left(\dfrac{45}{11}+\dfrac{7}{11}-\dfrac{8}{11}\right)\)
\(=\dfrac{3}{4}\times4\)
\(=3\)

`9/4xx15/11+3/4:11/7-3/4xx8/11`

`=3/4xx15/11xx3+3/4xx7/11-3/4xx8/11`

`=3/4xx45/11+3/4xx7/11-3/4xx8/11`

`=3/4xx(45/11+7/11-8/11)`

`=3/4xx4`

`=3`

\(\dfrac{27}{86}\) < \(\dfrac{27}{81}\) = \(\dfrac{1}{3}\) = \(\dfrac{9}{27}\) < \(\dfrac{25}{27}\) 

Vậy \(\dfrac{27}{86}\) < \(\dfrac{25}{27}\)