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

Explain how?

What type of tree can I carry in my hand?

What can go through glass without breaking it?

A bank customer had $100 in his account. He then made 6 withdrawals. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
$50 $50
$25 $25
$10 $15
$8 $7
$5 $2
$2 $0
----- -----
$100 $99

Why are the Totals not tallying?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

How many times can you subtract the number two from the number fifty?