It’s the way Jesus taught.The Pharisees didn’t like his approach much. They wanted facts, rules. He got to the heart of the matter. He was able to sum up the 10 commandments in two principles. His approach frustrates the flesh but gives life to the spirit. There are more examples of His teaching methods than I can list here but I recommend the book Teaching Techniques of Jesus by Herman Horne.
You can teach multiple levels because you are teaching the seeds of the subjects , so you can easily adjust it for different ages. More seed for older children, little bites of kernels for younger ones.
There is proven success teaching from Biblical principles. America’s founding fathers were educated by principles and were able to reason from God’s word. Their excellent reasoning and ability to form our constitution were a result of their Biblical education.
The subjects are alive in His word and it makes each subject exciting and important when you see how it fits into His Story.
You learn how to learn by beginning with the foundation of a subject. The steps to discovering Biblical principles apply to any subject at any time and carry across the curriculum.