algebra

It's not algebra ! Its arithmetic (for 12 year olds).
Add the area of the square to the area of half a circle radius 5.

(By the way, you should know by now that capital letters are used mainly for points/corners in geometric figures .Seeing capitals is an immediate indication for you to draw a diagram)

Fresco, the point E could be either inside or outside the square ABCD. If E is outside it would be the sum of the two figures. If E is inside the difference.

You're right about your advice--it's geometric. Poyla would recommend "draw the problem first" to understand how to solve it.

Rap

No chance ! In the absence of the word "inscribed" the default mode is for a summation interpretation of the word "figure". The simplistic level of the question reinforces this.