Remember that there are 1000 ml in 1 litre.
For mixed quantities, you should convert to litres or to millilitres.
Example
How many 150 ml glasses can be filled from a 1 litre bottle?

Answer
We convert 1 litre to ml so that we are working entirely in ml.
We need to work out 1000 ÷ 150.
This is equal to 100 ÷ 15 = 20 ÷ 3 = 6 r 2
So 6 glasses can be filled.
6 x 150 = 900, so 100 ml will remain in the bottle.