What goes up but never comes down?

What does this Rebus Picture means ?

Can you solve the maths in the below-given picture equation?

What breaks yet never falls, and what falls yet never breaks?

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?

What does the below image rebus riddle means ?

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?

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?

If an electric train is travelling south, then which way is the smoke going?