Your job is to sweep 3/4 of the school's cafeteria. Your friend agrees to help you and sweeps 1/3 of your part. What fraction of the entire floor your friend agreed to sweep? What fraction of the the entire cafeteria floor you will have to sweep?
A quick multiplication of 1/3 and 3/4 = 3/12 = 1/4
So, your friend will complete 1/4 of the job So, your part now is 3/4 - 1/4 = 2/4 = 1/2 You will sweep only half the cafeteria
Alternatively, you could write 3/4 = 1/4 + 1/4 + 1/4
and argue that you have 3 jobs to do consisted of 1/4, 1/4, and 1/4
If your friend takes 1 out of these 3 jobs, it means 1/4.
