This document provides information on calculating percentages of numbers and dealing with percentage problems. It discusses: 1) How to calculate a percentage of a number by replacing the % with a decimal and multiplying. For example, 225% of 24 is 2.25 x 24 = 54. 2) A trick for breaking percentages into 10% increments, like calculating 60% of 42 as (50% of 42) + (10% of 42). 3) Common mistakes made when dealing with percentages that are increased or decreased by a certain amount, like confusing "increased by 200%" versus "increased to 200%". 4) How to calculate the percentage one number is more or less than another, and examples of