How do you subtract an integer from another integer without using a number line or counters? give an example

The integer subtraction is goverend by the following the simple rules that the subtarction is normal as the natural numbers but the sign of bigger number comes in the final result. For example: -47 is to be subtracted from + 50 then, result = 50-47 = +3. But, see another example, If -7 is to be subtracted form -8 then , we will write as -8 -(-6) = -8 + 6 = -2. These rules are followed : (-)(-) = + and (-)(+) = - and (+)(+) = +

I’m not absolutely sure but i think it’s 7x6x5x4x3x2=5040 because as the first character you can take any of the 7 given then you are left with 5 then 6 then 4 etc.