When good multiplication and division skills with decimals are needed and why they are important

They are needed in things such as money when calculating tip and splitting up the bill.

Money because you might need to split up your money

5.5 miles over 2 hours--> 5.5/2= 2.75 miles per hour was his average walking speed. 5.5 miles over 2.5 hours --> 5.5/2.5= 2.2 miles per hour on the return trip meaning that his average speed was (2.75-2.2= 0.55) 0.55 miles per hour lower on the return trip