what does the below math rebus puzzle mean?

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

Who is He ?

What number should come in place of the question mark below?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

A Shopkeeper sold a few chickens to four different customers on a particular day. It was such that each customer purchased half of the remaining chickens and half the chicken more.

Can you find out how many chicken were sold by the shopkeeper on that day if we tell you that the fourth customer bought a single chicken ?

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?