Missing に particle: ごろ vs ごろに


I am studying Genki I at the moment and I stumbled across the following
sentence:

私はよく **七時ごろ** うちへ帰ります

I understand that the meaning is "I often return home at around 7 o'clock".
But I feel like we are missing the に particle after 七時ごろ here.

Does ごろ / ごろに _**replace**_ the に particle? If so, what is the difference
betwen them two?




に can be omitted after ごろ. The following two sentences are both correct and
they mean the same thing.

> 私はよく七時ごろうちへ帰ります
>
> 私はよく七時ごろ **に** うちへ帰ります

By the way, you can use ぐらい instead of ごろ, but in this case に can’t be
omitted.

> x 私はよく七時ぐらいうちへ帰ります

It must be:

> 私はよく七時ぐらい **に** うちへ帰ります




に can be omitted after ごろ. The following two sentences are both correct and
they mean the same thing.

> 私はよく七時ごろうちへ帰ります
>
> 私はよく七時ごろ **に** うちへ帰ります

By the way, you can use ぐらい instead of ごろ, but in this case に can’t be
omitted.

> x 私はよく七時ぐらいうちへ帰ります

It must be:

> 私はよく七時ぐらい **に** うちへ帰ります

