Can you solve this picture maths equation?

What is black when you buy it, red when you use it, and gray when you throw it away?

Can you solve the below geography rebus by decoding the below rebus ?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

1. What does:
TIM JOB
represent?

2. What does:
MO_ _
represent?

What is the difference between a jeweller and a jailer?

Its something that each of us devours,
Not just us but birds, beats, trees, and flowers,
Frets iron and nibbles steel,
Toil hard stones to meal,
Exterminates king, collapse town,
And blows the mountains down.

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?

What does this simple rebus mean?

It belongs to you, but other people use it more than you do. What is it?