I am doing sums.

I am doing sums.

Explanation

Present Continuous Tense

Active Voice: Subject + is/am/are + First of verb + ing + obect.

Passive Voice: Object + is being/am being/ are being + third form of verb + by + subject.


Active Voice: I am doing sums.

Passive Voice:  Sums are being done by me.

Do is a regular verb which means کرنا

Do means perform.

Did is the second form while done is the third form of Do.