(3965 - 2378 ) - ( 437 - 1378 ) - 528

= 3965 - 2378 - 437 + 1378 - 528

= ( 3978 - 437 - 528 ) - ( 2378 - 1378 )

= 3000 - 1000 

= 2000

$a,\frac{3}{4}<\frac{3}{2}$

$b,\frac{2}{-5}>\frac{3}{5}$

$c, \frac{-7}{3}>\frac{-7}{4}$

$d,\frac{-5}{6}<\frac{63}{-70}$

Chúcbạnhọctốt!

a, ( a + b - c ) - ( a - b + c ) 

= a + b - c - a + b - c

= ( a - a ) + ( b + b ) + ( - c - c )

= ( -2c )

b, ( 5 + 7 - 8 ) - ( 5 - 7 + 8 ) 

= 5 + 7 - 8 - 5 + 7 - 8

= ( 5 - 5 ) + ( 7 + 7 ) + ( - 8 - 8 )

= 0 + 14 + ( -16 )

= 14 + ( -16 )

= -2