a) (1200+60) : 12=1260 : 12=105
b) (2100-42):21=2058:21=98
\(\left(a\right)\left(1200+60\right)\div12\)
\(=1200\div12+60\div12\)
\(=100+5\)
\(=105\)
\(\left(b\right)\left(2100-42\right)\div21\)
\(=2100\div21-42\div21\)
\(=100+2\)
\(=102\)
\(\text{Đảm bảo đúng! mình học rồi!}\)
a) ( 1200 + 60 ) : 12
= 1200 : 12 + 60 : 12
= 100 + 5
= 105
b) ( 2100 - 42 ) : 21
= 2100 : 21 - 42 : 21
= 100 - 2
= 98