Question

bo dau ngoac roi tinh: a)  (27+65)+(346-27-65)         ;b)(42-69+17)-(42+17)

Answer 1

a/ (27 + 65) + (346 - 27 - 65)

= 27 + 65 + 346 - 27 - 65

= (27 - 27) + (65 - 65) + 346 

= 346

b/ (42 - 69 + 17) - (42 + 17)

= 42 - 69 + 17 - 42 - 17

= (42 - 42) + (17 - 17) - 69

= -69

Answer 2

a)(27+65)+(346-27-65)

=  27+65+ 346-27-65

=  (27-27)+(65-65)+346

=                346

b) ( 42-69+17)-(42+17)

=   42-69+17 - 42-17

= ( 42-42) +( 17-17)- 69

=                  -69