3rd hard-ish question

A=16

B=8

so 

16+8=24                            Caution I am not sure if I a supposed to do the stuff on the bottom so I would wait for a user just to make sure! Thanks for understanding. :) 

But we start with A which is 16*1*1=16

then B which equals 8 so 8*2*1=16  

16+16 = 32sq units 

A  is the surface area of a  16 units  by  1 unit  by  1 unit  right, rectangular prism.

In square units,   A   =   2(1)(1) + 2(1)(16) + 2(1)(16)   =   2 + 32 + 32   =   66

B  is the surface area of a  8 units  by  2 units  by  1 unit  right, rectangular prism.

In square units,   B   =   2(1)(2) + 2(1)(8) + 2(2)(8)   =   4+ 16 + 32   =   52

So....

| A - B |   =   | 66 square units  -  52 square units |   =   14 square units

hectictar: I actually knew quite some time ago that your "username" was a anagram of  what you wanted to become when you finished your school! I knew that from your beautiful drawings. You will make a great "Architect"!,

$\text{A} = 2(1\cdot 1) + 4(16\cdot 1) = 66 \text { square units}\\ \text{B} = 2(8\cdot 2) + 2(8\cdot 1) + 2(2\cdot 1) = 52 \text { square units}\\ |\text{A} - \text{B}| = 66 - 52 = 14\text{ square units}$