If '+' means '-', '-' means '$\times$ ', '$\times$ ' means '$÷$ ' and '$÷$ ' means '+', then what is the value of $12÷23\times 23÷10$ ?

First, let's substitute the original signs with their coded mathematical operators:
* Change $÷$ to $+$
* Change $\times$ to $÷$

The expression becomes:

$$12+23÷23+10$$

According to the BODMAS rule, perform division first:

$$23÷23=1$$

Now substitute it back into the expression and perform addition:

$$12+1+10=23$$