1. Are these two the same?

6-5/8"

and

6 5/8"

Wondering why the dash is used or is it just another way to write it out? Are both of these six and five eighth inches?

2. What is this?

3/4-1"?

Is this the same as 1-3/4" How would you pronounce that?

3. Is this [three and five eighth inches width x four and five eighth inches height x eight feet zero inches length? Width always comes before height correct?

3-5/8” x 4-5/8” x 8’-0”

4. Last question, is this pronounced two point 1 (2.1) inches x four point zero four (4.04) inches?

2.10” X 4.04”

Thanks guys!!