PEMDAS is very helpful. Without pemdas, people solve equations differently. For example, 2 + 3 * 2. Using pemdas, we knoow 2 + 3 * 2 = 8
However, without pemdas, someone could do 2 + 3, which is 5, then *2. Which would get 10.
PEMDAS is important to keep order.