{Beginner} Why Variable - 1 return original variable value of the variable. Why it does not decrement

I know its a very beginner question Here is scenario

Let number = 5; 
number - 1;
console.log(number);

it shows 5, why it does not show 4;

I want to understand this below recursion. Here times-1 is passed each time function is called. How it reaches to zero? And how each time decremented value is passed.

 if(times < 0) 
   return "";
 if(times === 1) 
   return string;
 else 
   return string + repeatStringNumTimes(string, times - 1);
}
repeatStringNumTimes("abc", 3);```