penalty for punctuation mark

[dellp]

Hello teachers!

I just want to ask the standing policy on checking papers for grade 3 English activity. My son was penalized by 1 point in the activity on subject and predicate topic wherein they will write sentences out of the picture displayed indicating the subject and predicate. He did the 5 sentences right except he missed to put period on 3 sentences. With this he was deducted 1 point. On their topic outline, refresher topic about punctuation mark is yet to follow. Although I myself used to stress this kind of neglect to my child I still want to clarify if this way of checking does not deviate to the objective of the activity.

Thank you so much for your kind advice.