What could cause an ORA-00936 - Missing Expression with the following sql?

select (select count(*) from gt_roster where ROS_ROSTERPLAN_ID = RPL_ID)
from gt_rosterplan
where RPL_ID = 432065061

SQL> select (select count(*) from emp2 where empdeptno = deptno)
  2  from dept
  3  where deptno=10
  4  /

(SELECTCOUNT(*)FROMEMP2WHEREEMPDEPTNO=DEPTNO)
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