B).2003-4006+6009
=(2003+4006)-6009+6009
= 6009-6009+6009
=6009
a) ( - 125 ) - [ ( - 125 ) + 225 + 75 ]
= - 125 + 125 - 225 - 75
= ( 125 - 125 ) - ( 255 + 75 )
= 0 - 300
= - 300
b) 2003 - 4006 + 6009
= 6009 + 6009
= 6009 x 2 = 12 018
ý nhầm, câu b mk lm sai nha
b) 2003 - 4006 + 6009
= - 2003 + 6009
= 4006