81 x 9 = 801. What must you do to make the this equation true?

A sundial has the fewest moving parts of any timepiece. Which has the most?

Buy me, smell me or deliver me, I do not change.

Who am I?

I hide my treasure in the ground, my tail is big and fluffy. If you spot me in a tree, please don’t call me scruffy. What am I?

Replace the question mark with the number below given a simple math problem.

If it took eight men ten hours to build a wall, how long would it take four men to build it?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

What does the below rebus riddle means?