Ooops… something went wrong. Why did we get something so odd?

The type of columns weight and height is real, which is a floating point number. The internal representation here is binary arithmetic. It means that not all decimal numbers can be represented exactly. The computations are also not performed exactly - as we can see.

What can be done about it? Nothing :) That's the way binary arithmetic works. If you need exact computations, you have to use a decimal type.

Something to remember: When you deal with money values, you should always use a decimal type. Floating point numbers are for "scientific" computations on various measurements, like weight and height.