How to add values using numberic in sql and update tat table column whenever i add o less?

hi i stuck with my query..
in my sql table contains tblCash
column name cCash and cDate
in aspx page
txtCash
btnAdd and btnLess
when i add cash it should add to cCash column and update with that remaining amoung..for example cash in cCash column is 5000 when i add 1000 and if i click btnadd it shuld add to tat column and update the record and like for less it should less from cCash column can any one suggest me how to give query..o stored procedure..
and this cash amount i want to add in another table
in tblCashUpdate with date and amount please help me..thank u