Explanation:
we can easily count this, as the diagonal lines are squares truly in half. so, 2 such cut squares are in total 1 full square.
there is one central rectangle of 4×6 squares = 24.
then in the upper left corner there is a small 2×2 square = 4.
and then we have in the bottom left 2 and the bottom right also 2 small triangles (4 in total) with each having 1 full square and 2 half-squares (2 squares in total) as area.
so, 4×2 = 8 squares.
so, the whole area is
24 + 4 + 8 = 36