I don't understand Mixture and pure substance?

Question

What is the diffrence between the two I want to know it perfectly my book is not clear

Answer 1

a mixture is made up with more than one substance.
a pure substance is when all particles are t he same in a substance

Answer 2

a pure substance is a single element or compound. A mixture contains more than one pure substance.

A solution is a particular kind of mixture, called homogenous, because the different materials are so uniformly mixed. So water and salt are pure substances, but if you dissolve the salt in the water you have a mixture. Air is a mixture of different substances, mainly oxygen and nitrogen.

Actually, this kind of thing is pretty easy to understand, as long as you don't expect it to be difficult.