A=5; B=-4;
              A + B = 1
              A - B = 9
              A * B = -20
              A / B = -1.25
truncate      A / B = -1
round next    A / B = -1
round down    A / B = -2
round up      A / B = -1
remainder of  A / B = 1
A to the power of B = 16E-4
A to the power of B = 16E-4