Blackboard bold letters used in mathematics

Have you ever seen really fancy letters that look kind of like they're drawn with chalk on a blackboard? Those are called blackboard bold letters, and they're often used in math to make certain things stand out.

So, imagine you're learning math and your teacher writes the letter "R" on the board. That doesn't really give you any clues as to what's special about "R". But if they write a fancy, blackboard bold "R", it's like they're saying "Hey, pay attention! This 'R' is a special kind of 'R' that we're going to use in a special way!"

Blackboard bold letters are also used to represent specific sets of numbers or mathematical concepts. For example, the blackboard bold "N" is used to represent the set of natural numbers (like 1, 2, 3), while the blackboard bold "Q" represents the set of rational numbers (like fractions).

So to sum it up, blackboard bold letters are a fancy way of writing letters that help highlight important mathematical concepts and sets of numbers.