What does this rebus riddle means ?

What number divided by 4 is the same as that number minus 4?

There is a hypothetical state between the USA and Mexico border 'Tango'.
Here 70 percent of the population have defective eyesight, 75 percent are hard of hearing, 80 percent have Nose trouble and 85 percent suffer from allergies, what percentage (at a minimum) suffer from all four ailments?

Optical Illusion: A cat is hiding in plain sight in the backyard. Only the most observant eyes can spot the cat in 7 seconds. Can you? Test your eye power now!

What is always in front of you but can’t be seen?

If,
9 * 8 * 7 = 65
8 * 7 * 6 = 50
7 * 6 * 5 = 37

Find
6 * 5 * 4 = ?

What does below chemistry rebus means?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

What will you call your mother's brother's brother-in-law?

Replace the question mark with the number below given a simple math problem.