# Watch What This Old, Mechanical Calculator Does When You Try to Divide by 0 You might remember from your earliest math classes that you cannot divide any number by zero. [Scroll Down For Video]

If you try to do this on a modern calculator, you’ll simply get an error. However, what happens when you try to do it on an old school, massive mechanical calculator.

Well, thanks to Youtube, now you can see exactly what happens. A Youtube user attempts to divide by zero on this old school Facit ESA-1.

The results are… interesting.

IFLS does a great job explaining why this simply doesn’t work:

As YouTube channel Numberphile explains, division is based on subtraction. If you want to divide a number by a second number, you simply subtract the second number from the first over and over again. For example, 20 divided by 5 would be: 20 – 5 = 15, 15 – 5 = 10, 10 – 5 = 5, 5 – 5 = 0. Since that took 4 subtractions, the answer is 4.

However, divide 20 by 0 and you’ll end up subtracting 0 from 20 an infinite amount of times. While that doesn’t mean that 0 equals infinity, it appears that the mechanical calculator is attempting to complete the infinite number of operations it believes it needs to complete the division. You can check out this Numberphile video if you want to know more about dividing by zero and why it doesn’t equal infinity.