Question

tính bằng cách hợp lí

a ) 27 + 45 + 18 + 81

b) ( 24 + 72+ 36 + 60) : 12

Answer 1

b) (24+72).(36+60):12=96.2:12

=192:12

=16

Answer 2

a)27+45+18+81

=3.9+5.9+2.9+9.9

=(3+5+2+9)9

=19.9=171

b)(24+72+36+60):12

=24:12+72:12+36:12+60:12

=2+6+3+5=16

Answer 3

chúc b học tốt nha

Answer 4

a) 27 + 45 + 18 + 91

= ( 27 + 45 ) + 18 + 91

= 72 + 18 + 91

= 90 + 91

= 181

b) ( 24 + 72 + 36 + 60 ) : 12

= ( 24 + 72 ) . ( 36 + 60 ) : 12

= 96 . 96 : 12

= 96 . 2 : 12

= 192 : 12

= 16