-1-(+4)=
solve the brackets first - + = -
=-1-4
=-5
-1+(-4)=-1-
solve the left side
-1-4=-1-
-5=-1-
now think what will be -5 if we -1 from it
-5=-1-4
-5=-5
-1- =-5
-1 minus what will be -5
-1-4=-5
-5=-5
1-(-4)=1+4
dove brackets first - -=+
1+4=1+4
5=5