Move four matchsticks to the below square to form three squares?

What has one eye, but can’t see?

If 1+9+8=1, what is 2+8+9?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

Two prisoners Jack and Jill are locked in a cell.
There is open window approx 40 feet above the ground of the cell.
They are never able to reach there.

Then they plan to escape by a tunnel and they start digging out.
After digging for more than 20 days, Jill comes with the different plan and they escaped.

what was the plan ?

A father's child, a mother's child, yet no one's son.

Who am I?

John was born on March 5, 1970, in Delhi, India. Jacob was born 25 days before John. The year when they took birth, Republic Day fell on Monday.

Can you find out on what day was Jacob born?