I teach individual classes as well as group classes and I use flash cards and games for both classes to help them learn. It’s important for teachers to be creative and be able to cater to the individual needs of the student. Every child learns differently so the method of teaching should accommodate to this. The younger child would probably benefit from group classes, like music appreciation, but at age 4+ or 5, a one-to-one would generally be quite suitable. Just make sure you find a teacher to suit your child. One who can build a good teaching relationship with the child.