I have a hard time with fractions so I usually just go into my calculator and change it to a decimal. For example with -5 1/3 I would insert 1/3 into my calculator to change it to a decimal and then simply tack on the -5 to it. So in decimal form 1/3 is 0.333... so with the -5 added on its -5.333... Do the same for the other number and then divide. You will get -1.9393... all you have to do is go into your calculator and try out 11/12 or 31/33 to see which equals 0.9393... because those are the only options with a -1. In this case 31/33 equals 0.9393 s -1 31/33 is the answer
The temperature is 3 degrees less then it was at lunchtime when he went to bed you didn’t ask a question or explain it so I’m assuming this is what you meant
