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

`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`

bang 8/5 nhe

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

=1+3/5

=5/5+3/5

=8/5

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 

= ( 1 + 12 ) + ( 2 + 11 ) + ( 3 + 10 ) + ( 4 + 9 ) + ( 5 + 8 ) + ( 6 + 7 ) 

=     13         +     13       +     13       +      13     +    13      + 13

=               13 x 6 

=                 78

sai thui

1+2+3+4+5+6+7+8+9+10+11+12

=(1+9)+(2+8)+(3+7)+(4+6)+(5+10)+(11+12)

=10+10+10+10+15+23

=10×4+15+23

=40+15+23

=55+23

=78

ủng hộ nha có gì sai sót mong bạn thông cảm cho !!!

1 + 2 + 3 + 4 +5 + 6 + 7 + 8 + 9 + 10 +11 + 12

= ( 12 + 8 ) + ( 11 + 9 ) + ( 7 + 3 ) + ( 6 + 4 ) + ( 10 + 2 + 3 ) + 1

Mình cũng không biết nữa !

6 650 + 9 543 + 3 250 – 9 900

= (6 650 + 3 250) + 9 542 – 9 900

= 9 900 + 9 542 – 9 900

 = 9 900 – 9 900 + 9 542

 = 0 + 9 542 = 9 542

6 650 + 9 543 + 3 250 – 9 900

= (6650 + 3250) + 9542 – 9900

= 9900 + 9542 – 9900

 = 9900 – 9900 + 9542

 = 0 + 9542 = 9542

câu này đúng đấy

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

2

= 2

( 7/4+5/4) x 5/3= 12/4 x 5/3 = 3 x 5/3= 5

5

5

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

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

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

cảm ơn

1,15 * 103 1,15 * 2 - 0,115 * 86 - 0,115 * 27

= 1,15 * (103 + 2 ) - 0,115 * (86 - 27)

= 1,15 * 105 - 0,115 * 59

=120,75 - 6,785

= 113,965