How to make a number out of other numbers in mathematica?

Question

I’m not entirely sure if this is possible, but I would like to make numbers composed of other numbers. For example, given $a$, $b$, and $c$, I’d like to make a number such that the digits are $a.bc$.

So, if $a = 1$, $b = 2$, and $c = 3$, we would have the number $1.23$. Is this possible?

Thanks!

Answer 1

I think what you want is:

 FromDigits[{a, b, c}] // Simplify

100 a + 10 b + c

For your example:

 FromDigits[{1, 2, 3}]/100.

1.23

Answer 2

Yes, as long as you know what you want to do and you do the mathematics correctly, go ahead and create new numbers out of the old ones.

That is a good way to understand numbers better.

They have created the set of positive integers starting at 1 and adding one each time.

$$1, 1+1=2, 2+1=3,....$$