My Favorite Photoshop Tool

I'm not a very computer savvy person. so when I started my photo shopping course at the beginning of this month, I was lost. Usually when I get lost in a course i just try a few different techniques until i figure things out. This time was no different. On the first say of the course, my professor had us use some tool to crop one part of picture and place it in another picture. It was a bit too complicated for me me so i started playing around with different tools to see what they did. Then I came across the eraser tool. I found this tool to be much easier than using the cropping tool. I can just erase what i don't wan't in the photo and because the eraser comes in multiple sizes, I can erase a lot more neatly.