which one is correct and please provide me the example

1) Helen will come to office later today

2) Helen will come to office around 10:00 today

3) Helen will coming to office around 10:00

4) Helen came to office later today
1, 2 and 3 are all correct.

4 is not correct as by using 'came' you are now speaking after the event.
Pardon me, Nona, but #3 is not correct unless it is changed to "will BE coming."
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Oh yes sorry, I didn't spot that. You are right.
How will the sentences be different if we put the "at" before the "around"?

Helen will come to office at around 10:00 today.

Helen will be coming to office at around 10:00.

I have difficulty in distinguishing proper incidences where the "at around" will suffice and where just the "around" will be good. Help me.
Actually there is another error as well, I was sloppy in only really reading the verb options, but all of the sentences should say 'to the office' and not just 'to office'.
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[W] Thanks Dear All !!!