I have attached a file of question #17 that says to "Complete the bar model and explain how to use it to find the unknown part." In the attached file, you will see the two rectangles--one with a blank (I guess) and the other a shaded square. There's also a line that I think is showing that the two rectangles are connected. Beneath that is another "blank".
How should this be shown? Using braille or tactile graphics? What is the "blank"?