10+10 and 11+11 can give you the same answer.

Explain how?

What is black when you buy it, red when you use it, and gray when you throw it away?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

How can a man go eight days without sleep?

What word is represented by this rebus?

A man is approaching a broad and barren land. He has a package with him. If somehow, he is unable to open the package before reaching the land, he will die.

Can you guess what is present in the package?

How can you take 2 from 5 and leave 4?

When it is alive we sing, when it is dead we clap our hands. What is it?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?