Common Math Mistake 1

Division by Zero
Everyone knows that 0/2 = 0 , the problem is that far too many people also say that 2/0 = 0 or 2/0= 2! Remember that division by zero is undefined! You simply cannot divide by zero so don’t do it!
Here is a very good example that can arise when you divide by zero. See if you can find the mistake in the work below.
So, we’ve managed to prove that 1 = 2! Now, we know that’s not true so clearly we made a mistake somewhere. Can you see where the mistake was made?
The mistake was in step 5. Recall that we started out with the assumption a = b .
However, if this is true then we have a -b = 0 ! So, in step 5 we are really dividing by zero!
That simple mistake led us to something that we knew wasn’t true, however, in most cases your answer will not obviously be wrong. It will not always be clear that you are dividing by zero, as was the case in this example. You need to be on the lookout for this kind of thing.
Remember that you CAN’T divide by zero!