Here is a little exercise designed to make using the math keys exponentially easier (pun intended!).
Basically, this is just an 8-keystroke pattern repeated 4 times, and then another 4 times with the shift key down for the math keys. This will make you get used to having your right-hand pinky go from its comfortable position in the home row to its outstretched, extended position for the math keys in the top numbers row. It's a pretty good pinky workout!
It's perfectly ok to move your whole hand as you reach to the math keys. What is most important is that your hands remain comfortable and relaxed the entire time.
Try to really feel the rhythm when you do this one! Do it as many times as it takes to make the movement feel completely natural.
When you feel you've really got this mastered, go back and do the Math Keys lesson.