= 26 . ( 13 + 7 ) - 17 . ( 9 + 11 )
= 26 . 20 - 17 . 20
= 20 . ( 26 - 17 )
= 20 . 9
= 180
b)
= ( 35 . [ 23 + 37 ] ) : 60
= ( 35 . 50 ) : 60
= 175 : 60
= \(\frac{175}{60}\)
c)
= ( 257 . [ 139 - 39 ] ) : 100
= ( 257 . 100 ) : 100
= 257
d)
= ( 102 - 72 ) + ( 90 - 60 ) + ( 54 - 84 ) + ( 48 - 78 ) + ( 66 - 96 )
= 30 + 30 - 30 - 30 - 30
= 30 x 2 - 30 x 3
= (-30)
cảm ơn bạn nha