Yesterday Lucas asked when Kevin was coming home. I told him that he would be back on Friday. Though Lucas knows the days of the week, the timing of those days is not totally clear yet.
So I made this nifty little calendar for Lucas.
Every day, he can put an X on a new day. It worked because today after he put in his X, he looked at the blank squares and said, "Daddy will be home in 3 days!"