Missing Basic Human Knowledge

So, this was written because someone asked me what 4 times 80 is and I simply do not have this knowledge. I remember having to learn about this in... third grade? But I failed.

My dad always scolded or punished me for not being able to do math, but I don't recall him trying until maybe one time when I was already in my mid-teens (did not end well). I actually asked my boyfriend if he thought parents were supposed to help their children learn what they teach in school. He seems to think so, but it simply seemed inconsiderable up until now for me.

Now I am a 27 year old woman who has never learned to answer basic math problems without a calculator. No idea how I passed a college algebra course this way, but I managed. Despite this, I cannot survive without a calculator and I am very upset about it.

I even use a calculator for simple addition problems regularly.

How normal is this...? Is it so bad if I never actually learn this skill in my lifetime?