Date::Calc is your friend.

use Date::Calc qw( Add_Delta_YMD );

my ( $curyear, $curmonth, $curday ) = ( 2002, 1, 1 );
my ( $deltayear, $deltamonth, $deltaday) = ( 0, 0, -14);

my ( $year, $month, $day ) =
  Add_Delta_YMD( $curyear, $curmonth, $curday,
                 $deltayear, $deltamonth, $deltaday );
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