Medicare supplement plan A is the first of the Medicare plans that was designed to supplement existing coverage. Medicare, even when it was first launched in 1965, was not designed to be an all-encompassing healthcare product. It was simply created to take the edge off of the medical expenses that senior citizens experience. Over time, the healthcare industry and the economy have changed drastically. Rather than overhauling the entire Medicare system, the government decided to implement 12 plans for supplemental coverage and two variations of plans F and J with higher deductibles and lower monthly payments, so that people could get complete healthcare.