sorry i don't get what you are trying to say: isn't (Number of days from 1 January to 30 June) / (Number of days from 1 January to 30 June) = 1?

sorry if i missed something.

Yes, you are right if you were in service during the said period and have worked throughout that period with no 'No Pay Leave' or other leaves which resulted in the deduction of your work days. Consideration has to be given to those who joined service within that period but not from the start of the said period.

0.35 month + one off payment for Bicentennial Year

Not i say, but a friend of a friend of a friend say...

just wondering if i start on Jul 1st, do you think i can still qualify for the Bicentennial Bonus? I know definitely not possible for Mid-year.

If a person leaves service before 30 June, will he/she still qualify for mid year bonus?

When will the announcement be

Typically 15-20 June

No. The person needs to stay one month after the payment. The only exception is the person leaving due to retirement or alike. Those who resign within one month after payment or dismissed will not receive.

Previous two years were on 19 June 2019. Should be on the third week of June 2019.

There is no bicentennial bonus or at least as of now, there is no announcement of it yet. Depending on the payment period, it is mid-year and you join in July, then the answer is No.