So when you have a -(-) then you make that a positive so that would mean - (+) so the two - - are positive and just one - is still negative, which would mean that the answer is -3. Because if the negative is greater that the positive then it is still a negative, in your mind you should make 13 positive minus 10 and then add the negative to make things easier if you want to.
Because -13-(-10) you have to make the minus sign into Addtion because you already have a negative which then means you have to make the 10 into a positive
