If eleven plus two equals one, what does nine plus five equal?

What makes this number unique: 8,549,176,320?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

You have $100 with you and you have to buy 100 balls with it. 100 is the exact figure and you can't go below or above the numbers and you have to use the entire $100. If there is no kind of tax applied how many of each of the following balls will you be able to buy:

Green Balls costing $6
Yellow Balls costing $3
Black Balls costing $0.10

Now, how many of each must you buy to fulfil the condition given?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

I’m tall when I’m young, and I’m short when I’m old. What am I?

What can you deduce from the following BrainBat?

CRY
LMKI

I am white when I am dirty, and black when I am clean. What am I?

Replace the (?) with the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59