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?

Can you find the missing piece of the Porsche?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

Count the number of times the letter "F" appears in the following paragraph:

FAY FRIED FIFTY POUNDS OF
SALTED FISH AND THREE POUNDS
OF DRY FENNEL FOR DINNER FOR
FORTY MEMBERS OF HER FATHER'S FAMILY.

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Do You See It?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?