Pictures of math problems that have not been done.

Let the side length of the square in the lower right corner be x,

Then the side length of the square in the middle below is also x,

The side length of the lower left corner is (x+ 1).

The side length of the upper left corner is (x+2).

So the width of the rectangle is (x+ 1)+(x+2)=(2x+3),

The length of this rectangle is (x+ 1)+x+x=(3X+ 1).

The side length of the upper right corner is (3x+ 1)-(x+2)=2x- 1, so 2x- 1=x+3, and x=4 is obtained.

The two sides of the rectangle are 1 1 and 13, respectively, so the area of the big rectangle is11×13 =143.