Mission: fill in the gaps.
We discussed the equivocating language that has been used here ('likely', 'assuming', 'could cost', etc). We also talked about other Walls (in the West Bank, Cyprus, Korean peninsula, Berlin).
Are the figures in the image reasonable ones? Will it really be that high? Can a wall that high really be only a foot thick?
Our calculations gave us about 8.9 million cubic metres of concrete and a total estimated cost of $38 billion. Reasonably, my class wanted to round this off to $40 billion. The original Guardian article is linked below. Here is the image: