So, if you have -5/1-5/3 you have to find the LCD (least common denominator) so you can subtract them. The LCD would be 3 because the denominators would be the same and with 1 as a denominator its pretty easy. Then, you would multiply the numerator by 3 and you would get -15/3-5/3 and you can subtract normally. If you subtract correctly you should get -20/3. I really hoped this helped. :)