There are 1000 milliliters a in 1 liter. It’s easy if you have a decimal like 4.2. The 2 adds up to 200 milliliters. 4 liters x 1000 milliliters equals 4000 milliliters. It then becomes 4200 milliliters when you add the .2 from 4.2. If she has I milliliter for each snowboard, the instructor can wax 4,200 snowboards.