As shown in the figure, the trademark pattern designed by Sunshine Advertising Company for a certain product, the shadow part in the figure is diagonal, and if the area of each small rectangle is up, it is shaded. The meaning of the question can be 3,

The area of the shaded part =4×4- upper 5× upper 4-upper 5×3×3- upper 5×3×4

= upper -5-95- middle

= 3.7.

So the answer is 3.7.