tính bằng 2 cách : 143*[76+24] 345*[121-21]

Xin chào,xin chào^^

$a$,C$1$:$143(76+24)=143.100=14300$

C$2$:$143(76+24)=143.76+143.24=10868+3432=14300$

$b$,C$1$:$345(121-21)=345.100=34500$

C$2$:$345(121-21)=345.121-345.21=41745-7245=34500$