How can i show 5/8 is greater than 3/8

The first answer, using a number line, is a good answer.

I have two other ways:

Way #1:

5 stones is more than 3 stones.
5 gallons is greater than 3 gallons.
5 pounds is greater than 3 pounds.
5 puppies is greater than 3 puppies.
5 hamburgers is greater than 2 hamburgers.
5 schoolbuses is greater than 3 schoolbuses.

We look around us, and we see that 5 of anything
is always greater than 3 of the same thing.

There's no reason that should change if the 'things' are eighths.

Way #2:

-- Get 2 friends to help you.

-- Take one good-size veggie pizza or coconut cream pie.

-- Carefully cut it up in eight (8) equal pieces.
   Now each piece is 1/8 of the pie or the pizza.

-- Give 5 pieces (5/8) to the first friend.
   Give 3 pieces (3/8) to the other friend.

-- Ask them to get together and agree on who has more.

Make a number line <01/82/83/84/85/86/87/81>