How much is the maximum increase of the surface area when a cuboid wood of 20cm long, 5cm wide and 3cm high is sawed into two sections I don't know if the cross section is right

How much is the maximum increase of the surface area when a cuboid wood of 20cm long, 5cm wide and 3cm high is sawed into two sections I don't know if the cross section is right


To maximize the increase in surface area, the sawn section should be as large as possible
The maximum section is a rectangle 20 cm long and 5 cm wide
So the maximum area of sawn section is 20 × 5 = 100 square centimeter
And because a piece of wood is sawn into two sections, the surface area will be two more sections
So the maximum increase of surface area is 100 × 2 = 200 square centimeter