This is one of those embarrassing things that many adults don't know: measurement conversions. To my memory, we only spent fifteen minutes talking about conversions in class. That was back in the 2nd grade. They should have tested us every day on that. Nonetheless, it's not anyone's fault but yours for not knowing your conversions as an adult. You don't want to be the guy who checks the recipe and can't even make it because he doesn't know how many tbsps in a cl.
It's easy to rely on the internet for these things, but you can't retain knowledge by looking it up every once in a while. One day you won't have the internet with you. You better pray that it's not a life and death situation that relies on your knowledge of measurement conversions.