hamza::[PERSON]-DateOfBirth->[BIRTH]-ptime->[DATE = (5, 04, 1995)]. hamza::Age(A) :- currentDate(D1), hamza::[PERSON]-DateOfBirth->[BIRTH]-ptime->[DATE = D2], diffDate(D1, D2, A). currentDate((10, 08, 2000)). diffDate((x_Day2, y_month2, z_year2), (x_Day1, y_month1, z_year1), (x_Day, y_month, z_year)) :- val(x_Day, sub(x_Day2, x_Day1)), val(y_month, sub(y_month2, y_month1)), val(z_year, sub(z_year2, z_year1)), /.