Tính nhanh: c) [ ( − 5/7 ) + 3/5 ] : 2020/2021 + ( 2/5 − 2/7 ) : 2020/2021
Giải thích
c) [(−57)+35]:20202021+(25−27):20202021
=[(−57)+35].20212020+(25−27).20212020
=[(−57)+35+25−27].20212020
=(1−1).20212020=0.20212020=0
c) [(−57)+35]:20202021+(25−27):20202021
=[(−57)+35].20212020+(25−27).20212020
=[(−57)+35+25−27].20212020
=(1−1).20212020=0.20212020=0