Among the following, total number of meta directing functional groups is (Integer based) $$-OCH_3, -NO_2, -CN, -CH_3, -NHCOCH_3, -COR, -OH, -COOH, -Cl$$

Meta-directing groups are electron-withdrawing groups that deactivate the ring and direct incoming electrophiles to the meta position.

Analyzing each group:

- $$-OCH_3$$: Ortho/para director (activating, +M effect)

- $$-NO_2$$: Meta director (deactivating, -M effect)

- $$-CN$$: Meta director (deactivating, -M effect)

- $$-CH_3$$: Ortho/para director (activating, +I effect)

- $$-NHCOCH_3$$: Ortho/para director (activating, lone pair on N)

- $$-COR$$: Meta director (deactivating, -M effect)

- $$-OH$$: Ortho/para director (activating, +M effect)

- $$-COOH$$: Meta director (deactivating, -M effect)

- $$-Cl$$: Ortho/para director (deactivating but o/p directing due to lone pairs)

Meta directing groups: $$-NO_2, -CN, -COR, -COOH$$ = 4 groups.

The answer is $$\boxed{4}$$.