Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

What has no start, end, or centre?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Can you find the odd number in the following?

2716, 4135, 5321 and 7145

On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?

A bomb exploded in a room full of married couples and no one died. How?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?