There are 4 different grades represented, so for the first question, there are 4 ways that the students can sit if they must sit together by grade.
For the second question, there are 3 grades other than senior level, so it starts with 3 ways that the students can be seated. 3 ways x 2 students per way = 6 ways
if the temperature was at 15 and dropped to zero the amount it changed would be is -15. The integer is -15 because an integer is a whole number and it can also be a negative or positive number it just can not be a fraction
