I had exactly the same reaction. What in hell do they expect you to conclude from "28 672"?

The problem isn't the math, as universally known and calculated. The problem is the *expressed context* of whatever values are being presented.

You inserted a comma in the 'value(s)'....they could be taken many ways without that correlation being added. They could be ratios missing the colon, fractions missing the /....many things, but a space just doesn't compute....*literally and figuratively!*

The arithmetic as presumed is being presented is all very simple. It's trying to suss what exactly they're attempting to state in the way the figures are presented. Math if a lot more than just putting numbers in a string, spaced or otherwise.