How Do Percentage Points Work?

When there’s an election, the newspapers often write about the amount of support all the different parties have in an effort to give the readers an image of the political landscape. They might report that one party has the support of $30\text{\%}$ of the voters, and that this is an increase by $2.3$ percentage points compared to last month. When this percentage increases or decreases in the polls, you’re not given those changes in percentage change, but a change in percentage points. This works the same way as adding or subtracting with normal numbers, meaning that if a party with $30\text{\%}$ support gains $2.3$ percentage points, they now have $30\text{\%}+2.3\text{\%}=32.3\text{\%}$ support.