Add .50 pesos, then drop the fractional pesos from the result. Examples 13.40 is rounded as 13.40 + .50 = 13.90, drop the .90 to get 13 pesos. 6.75 is rounded as 6.75 + .50 = 7.25, drop the .25 to get 7 pesos.
Equivalently, if the fractional part is .50 or higher, round up to the next higher peso; otherwise don't.
Equivalently, if the fractional part is .50 or higher, round up to the next higher peso; otherwise don't.
