Ta có 1668+976+312-576=(1688+312)+(976-576)=2000+400=2400
1688+976+312-576
= ( 1688 + 312 ) + ( 976 - 576 )
= 2000+400
= 2400
1688 +976 +312 -576 =1688+312+976-576 = 2000+400 =2400
\(1688+976+312-576=1688+312+976-576\)\(=2000+400=2400\)
= {1688 + 312} + { 976 - 576}
= 2000 + 400
= 2400
1668+976+312-576
=(1688+312)+(976-576)
=2000+400
=2400
1688 + 976 + 312 - 576
= (1688 + 312 ) + (976 -576)
=2000 + 400
=2400