This is normal stuff, why can’t you get that?
Don't take it for granted though.
Shouldn't we be thankful we're able to have an ordinary day like today.
You've seen how 当たり means success. If you've experienced success before, everything after that seems to be pretty obvious.
The readings for this word are both kun'yomi readings. You've learned both of these readings by now so you should be able to read this on your own.