The focus for Day 9 is Algebraic notation and collecting like terms. Here we take an introductory look into Algebra and this will form the basis of all future algebraic manipulation. It will be important to know and understand the 'shortcuts' in algebraic notation. Using this knowledge, we are able to simplify expressions by collecting like terms together.
It is really important in this topic to pay attention to signs. Are you dealing with positives or negatives? If you gain a solid understanding of this topic it will help to enhance your Algebra skills and tackle more complex problems.