260 x 7369 : 13 = 1915 940 : 13 = 147 380 

\(\dfrac{7}{5}\times\dfrac{11}{24}\times\dfrac{5}{7}\times\dfrac{24}{55}\\ =\left(\dfrac{7}{5}\times\dfrac{5}{7}\right)\times\left(\dfrac{11}{24}\times\dfrac{24}{55}\right)\\ =1\times\dfrac{1}{5}\\ =\dfrac{1}{5}\)

\(\dfrac{7x11x5x24}{5x24x7x55}\)=\(\dfrac{11}{55}\)=\(\dfrac{1}{5}\)

= (7/5 x 5/7) x (11/24 x 24/55)

= 1 x 1/5

= 1/5

5 giờ 15 phút x 2 + 4 giờ 45 phút x 2 

= ( 5 giờ 15 phút + 4 giờ 45 phút ) x 2

= 10 giờ x 2

= 20 giờ

=( 5 giờ 15 phút + 4 giờ 45 phút ) x 2

= 9 giờ 60 phút x 2

= 20 giờ

\(50\times45\times2\)

\(=100\times45\)

\(=4500\)

\(78\times2\times5\)

\(=78\times10\)

\(=780\)

50 x 45 x 2 

= 45 x ( 50 x 2 )

= 45 x 100 = 4500

78 x 2 x 5

= 78 x ( 2 x 5 )

= 78 x 10 = 780

\(\frac{1}{2}\times\frac{3}{15}+\frac{13}{15}\times\frac{1}{2}-\frac{1}{2}\times\frac{1}{15}\)

\(=\frac{1}{2}\times\left(\frac{3}{15}+\frac{13}{15}-\frac{1}{15}\right)\)

\(=\frac{1}{2}\times1=\frac{1}{2}\)

~ Hok tốt ~

1/2 . 3/15 + 13/15 . 1/2 - 1/2 . 1/15

= 1/2 . ( 3/15 + 13/15 - 1/15 )

= 1/2 . 15/15

= 1/2 . 1

= 1/2

                            #Louis

\(\frac{1}{2}\times\frac{3}{15}+\frac{13}{15}\times\frac{1}{2}-\frac{1}{2}\times\frac{1}{15}\)

\(=\frac{1}{2}\times\left(\frac{3}{15}+\frac{13}{15}-\frac{1}{15}\right)\)

\(=\frac{1}{2}\times1\)

\(=\frac{1}{2}\)

Study well ! >_<

3046 x658+ 3046 x341 +3046
= 3046 x ( 658 +341 + 1 )
= 3046 x 1000
= 3046000

\(=21,37\cdot\left(27,5+72,4+0,1\right)=21,37\cdot100=2137\)

=21,37⋅(27,5+72,4+0,1)=21,37⋅100=2137

\(=21,37\cdot27.5+72.4+21.37+21.37\cdot0.1\)

\(=21.37\left(27.5+72.4+0.1\right)=21.37\cdot100=2137\)

=>2137