Can you please complete your question
If we are talking about whole numbers, the only number in between 1 and 3 is 2 but if we are talking about numbers in general, there are an infinite amount of numbers (for example, 1.1, 1.12, 1.004, and 1.80543285 are all in between 1 and 3).
I hope this helps you
0,644
644/1000
161/250
Well what i think you're asking here...I apologie if I'm wrong but what I did was
f(-1) = 4 * 7^t = 4/7
and
f(2) = 4 * 7^t = 196.
Is this what you wanted if not I can...try another way.