In cell C1 use the formula =INT(B1-A1) to get the days. Then you have to get the remaining hours, which is the formula =MOD(B1-A1,INT(B1-A1)) and represents the remaining time. So in cell D2 enter the formula =HOUR(MOD(B1-A1,INT(B1-A1))). In cell E2 enter the formula =MINUTE(MOD(B1-A1,INT(B1-A1))).
You can opt out of Medicare Part B and in some situations you should opt out. Most people are automatically enrolled in Medicare Part A and Part B when they turn age 65. And most receive Part B at no charge. Medicare Part B is optional and you may not need the coverage if you have a group health plan.
Once you enroll in Medicare you may no longer contribute to your HSA. For most individuals this means you will no longer be eligible when you turn 65. You lose eligibility as of the first day of the month you turn 65. For example, if you turn 65 on July 21, you are no longer eligible for an HSA as of July 1.