Let f : X longrightarrow Y be quasi-open. We show that: (1) If A $subset$ X is open, f│A is quasi-open, (2) f : X longrightarrow f(X) is quasi-open. (3) And let $f_{alpha}/,:X_{alpha}$, longrightarrow $Y_{alpha}$ be quasi-open. Then $Pi f_{alpha}, : Pi X_{alpha}$ longrightarrow $Pi Y_{alpha}$/ defined by {$x_{alpha}$} longrightarrow {$f_{alpha},({chi}_{alpha}$)}, is quasi-open. (4) Lastly, if $f_{i}: X_{i}$ longrightarrow Y are quasi-open, i = 1,2, then F: $X_1 igoplus X_2$ longrightarrow Y, defined by $F({chi})=f_i({chi})$, ${chi} in X_i$, is also quasi-open.