I look at you, you look at me, I raise my right, you raise your left. What am I?

What is at the end of a rainbow?

What has no start, end, or centre?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

John needs to purchase 100 chocolates from three different shops and he has exactly 100 rupees to do that which he must spend entirely. He must buy at least 1 Chocolate from each shop.

The first shop is selling each chocolate at 5 paise, the second is selling at 1 rupee and the third is selling at 5 rupees.

How many chocolates should he buy from each shop?

The more you take me, the more you leave me behind.
Who Am I?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Forwards I am heavy, backward I am not. What am I?