For #9 you divide by 2
For #10 you add up all 3 weights and divide it by 3.
For #11 you subtract ( 12 ft 8 in - 11 ft 11 in )
For #12 you divide 7 1/2 hours by 375 miles.
For #7 you multiply $4.50 by 5 and for the 18 inches, that equals 1/2 a yard, so you add the sum of $4.50 times 5 to half of $4.50.
For #5 you multiply $0.96 by 5, and 12 oz equals 3/4 of a pound. So you add 3/4 of $0.96 to the sum of ( $0.96 x 5 ).
For #8 you convert 6 yds 9 in into inches to get (6 x 12)+9 to equal 72 + 9 which equals 81. Next you divide 81 by 5 to get your answer.
If you want me to write out the equations for each, I will
Hope this helped
