When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

The dirtier I get, the whiter I look. Who am I?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

What has many keys but can’t open a single lock?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

What demands an answer, but asks no questions

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.