Bad/lost/Assumed Parenthesis
This is probably error that I find to be the most frustrating. There are a couple of errors that people commonly make here.
The first error is that people get lazy and decide that parenthesis aren’t needed at certain steps or that they can remember that the parenthesis are supposed to be there. Of course the problem here is that they often tend to forget about them in the very next step!
The other error is that students sometimes don’t understand just how important parentheses really are. This is often seen in errors made in exponentiation as my first couple of examples show.
Example 1 Square 4x.
Correct
Incorrect
Note the very important difference between these two! When dealing with exponents remember that only the quantity immediately to the left of the exponent gets the exponent. So, in the incorrect case, the x is the quantity immediately to the left of the exponent so we are squaring only the x while the 4 isn’t squared. In the correct case the parenthesis is immediately to the left of the exponent so this signifies that everything inside the parenthesis should be squared!
Parenthesis are required in this case to make sure we square the whole thing, not just the x, so don’t forget them!