To find how much a lemonade will be left over, you will convert 4.6 L to 4600 mL.
Then take the total 4600 mL and break them into groups that are 300 mL. Each group of 300 mL represents one bottle.
4600/300 = 15 1/3 bottles.
You can fill 15 whole bottles, leaving you with 1/3 of a bottle left.
1/3 of 300 mL is 100 mL.
There will be 100 mL left over after filling bottles.