What does this mathematical rebus means ?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

A very interesting trivia question for all.

Why do men's shirts have their buttons on the right side and women's have buttons on the left-hand side?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

what does this below rebus represent identXQQQQQME

I am the fastest animal but cannot climb the tree. What am I?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?