In math does per mean, addition or multiplication?

Question

narissa · Answer

@LunyMoony

photon336 · Answer

I guess let's take an example 

let's say you drive 70 miles per hour  

$$\frac{ 70~miles }{ hour }$$

narissa · Answer

addition? if someone rode a bike for 4.5 hours and his speed was 12 miles per hour wouldnt you add 4.5 and 12 to get 16.5 or multiplication

photon336 · Answer

well you could. @narissa but multiplication would be the more efficient way.

photon336 · Answer

$$\frac{ 12~miles }{ \cancel\hr }*(\frac{ 4.5~\cancel\hr}{ 1 }) = 54~miles$$

narissa · Answer

okay thank you

photon336 · Answer

@narissa think about if you wanted to find the total # of miles traveled. like i did above. if say if that person rode for 12 hours. it would take alot more time to keep adding that up. that's why you would multiply.