The Bubby (יוכבד) was counted when she was a baby, so Shevet Levi are counted when they are babies. Does that make sense?
Is there a מחלוקת between the Maharal and the Gra regarding how much Torah does it take to be called "כאילו ילדו"?
Why having a Geshmak in learning Torah is part and parcel of מצוות תלמוד תורה, and not so in other מצוות?
