at about
At approximately, as in We'll start at about nine. This phrase, most often used with respect to time (as at about four o'clock), is sometimes criticized for being redundant. Although one of the two words sometimes can be omitted without changing the meaning
for example, About four o'clock is when most guests will arrivein other instances both are needed, as in This stock is now selling at about its original offering price. [Early 1800s]