It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

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?

Two friends Smith and Andrew were talking about the bravery of their families. Smith told great stories about his courageous grandfather who fought for Britain in "World War I". Andrew told that his grandfather was so brave that in 1919 just after the war he was honoured with a bravery medal with the words "For our Courageous Soldiers In World War I" embedded into it. Smith knows that his friend is lying. How?

What English word has three consecutive double letters?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

I have eight fingers and two thumbs but I do not live. What Am I?

A man had five children. He had $100 with him to give to his children. He decided to start with the youngest child and then give $2 more than each younger child to his next elder child.

For example, if he gives $x to the youngest child, he will give $(x+2) to the next one, $[(x+2) + 2] to the next one and so on.

Can you find out how much did the youngest one receive?