7794 - ( 873 - 734 ) + ( 1873 - 794 - 734 )

= 7794 - 873 +  734 + 1873 - 794 - 734

= ( 7794 - 794 ) + [ (-873) + 1873 ] + (734 - 734 )

= 7000 + 1000 + 0

= 8000.

a.156*75+25*150

=156*25*3+25*150

=25*(156*3+150)

=25*618

=15450

b,791*101-791

=791*101-791*1

=791*(101-1)

=791*100

=79100

c,2*15*4*25

=(2*15)*(4*25)

=30*100

=3000

\(794\times101-794\)

\(=794\times\left(101-1\right)\)

\(=794\times100\)

\(=79400\)

\(2\times15\times4\times25\)

\(=\left(2\times15\right)\times\left(4\times25\right)\)

\(=30\times100\)

\(=3000\)

bang 2500 va 1672 nhe

a) 30 + 192 + 70 = 30 + 70 + 192

= 100 + 192 = 292

b) 50 + 794 + 50 = 50 + 50 + 794

= 100 + 794 = 894

c) 75 + 219 + 25 = 75 + 25 + 219

= 100 + 219 = 319

d) 725 + 199 + 125 = 725 + 125 + 199

= 850 + 199 = 1 049

\(\dfrac{14}{17}:\dfrac{17}{32}-\dfrac{14}{17}:\dfrac{17}{15}\\ =\dfrac{14}{17}\times\dfrac{32}{17}-\dfrac{14}{17}\times\dfrac{15}{17}\\ =\dfrac{14}{17}\times\left(\dfrac{32}{17}-\dfrac{15}{17}\right)\\ =\dfrac{14}{17}\times\dfrac{17}{17}\\ =\dfrac{14}{17}\times1\\ =\dfrac{14}{17}\)

\(\Rightarrow\dfrac{14}{17}\times\dfrac{32}{17}-\dfrac{14}{17}\times\dfrac{15}{17}=\dfrac{14}{17}\times\left(\dfrac{32}{17}-\dfrac{15}{17}\right)=\dfrac{14}{17}\times\dfrac{17}{17}=\dfrac{14}{17}\)

14/17.32/17-14/17.15/17

=14/17.(32/17-15/17)

=14/17.1=14/17

14/17 : 17/32 - 14/17 : 17/15

= 14/17 : (17/32 - 17/15)
= 14/17 : (-289/480)
= -960/289

=14/7:(32/15-17/15)

=14/7:1

=14/7

hc tốt

= 0

\(0\)

0