What does this below rebus puzzle mean?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Find the missing number in the image below.

What 5-letter word typed in all capital letters can be read the same upside down?

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

Why did Navjot Singh Sidhu put the new January calendar in the freezer