I don't know about the SQL commands themselves however if you want to assign the output of a command to a variable, you need to use the backtick marks.
Code:
cntADD=`sqlplus -s user/pwd select count(*) from tbl where...;`
cntCHA=`sqlplus -s user/pwd select count(*) from tbl where...;`
cntDEL=`sqlplus -s user/pwd select count(*) from tbl where...;`