1 teaspoon = 4.9mL, therefore 200mL =~ 40.8 teaspoons. just divide 200 by 4.9
Try going to
google.com and just enter the question in the search box like this:
200ml in tsp
and hit 'Search'
google's calculator function will do the conversion for you, and has a LARGE number of conversion factors built in to it; just put the 'known' number and units, followed by the
Word "in", and then the desired units!
18ft in cm
350 degrees f in degrees c
45 years in minutes
etc...