7 x 15 x 4 - 20 = 7 x ( 15 x 4 - 20 ) = 280
32 x 5 + 6 x 4 = (32 x 5 + 6) x 4 = 664
7 x 15 x 4 - 20 = 280
7 x (15 x 4 - 20) = 280
32 x 5 + 6 x 4
= (32 x 5 + 6) x 4 = 664
ủng hộ nha
7 x 15 x 4 - 20
= 7 x ( 15 x 4 - 20 ) = 280
32 x 5 + 6 x 4 = 664
= ( 32 x 5 + 6 ) x 4 = 664