if you are looking how to times a 2 digit witha 2 digit number there is a video where it explains everything.
if each block is 2/3 miles long, and he walks 4 1/2 blocks, we can simply multiply to two. It looks like this:
(2/3)(4 1/2)
to multiply, make 4 1/2 into an improper fraction and multiply normally
(2/3)(9/4)
Ton walks 3 miles total.
-16t^2+400=0
16t^2=400
take square root on both sides.

4t=20
t=20/4
t=5