Usage of "think on"

[Kute_Choc]

I've seen "...thinking on..." .Can you show me the use of "think" for this situation? Thanks in advance.

[Molly]

To me, it has two uses.

1. These three have the same meaning:

Think on how happy she would be if we get this job done by six.
Think about how happy she would be if we get this job done by six.
Think how happy she would be if we get this job done by six.

2. These three have the same meaning:

(Have a) Think on my offer and give me a decision by ten.
Think over my offer and give me a decision by ten.
Consider my offfer and give me a decision by ten.