This is indeed good advice! When I was in graduate school, I took a required math class. I'm fairly smart, but math has always been my weak spot. I had a lot of trouble with it, but usually 'got it' after a while. In grad school, any grade below a B was considered a failure, so I had to do well in the class.
One type of problem was giving me fits. It just wouldn't fit in my brain! There was a guy in the class - a math whiz - who offered to help me. We spent about 2 hours trying to pound that little bit of math into my brain. Finally, I said to him, "If I haven't gotten it by now, I never will." and called it quits.
Driving home I had a very strange experience. I actually felt the world move just a bit - no exaggeration, I really felt movement (Note that no earthquake was reported in the area), and my brain flooded with understanding for that particular bit of math!
I was absolutely delighted, thrilled and excited! When I got home, I told DH what happened, then called my friend to tell him what happened! Best of all, the next day I passed the test! God got a huge thank you for that one!
Sometimes we just have to get out of our own way and let our brain work on a problem in the background.