Replacing "the brick" with "a brick," I always thought the question was fine:

> A brick weighs one pound and half a brick.

I could easily imagine a brick being balanced by a one pound weight and a half brick on the other side, and the answer was easy.

I agree that "half the brick" is trickier wording.

The problem might have be created when bricks were hand made and there was no assumption that different bricks have same weight. So it was important to stress that it weighs 1 pound and half of itself.

Exactly. It would read better as "The weight of a brick is equal to one pound plus the weight of half an equivalent brick"

i.e. x = 1 + x/2

I could parse it fine but if I were writing this I would include more redundancy e.g. "weighs one pound and half the weight of the [maybe use our to suggest to the reader it's the same one] brick".

The well drilled student would be able to parse both but anyone who can struggle with getting the words into their head in the right order like me could struggle.

in this case, the line between grammar and math is fuzzy - english (or russian) and mathematical symbols are two different languages here which are each capable of describing the same thing.

the challenge is to do the necessary translation and rearrangement