The Rambam wrote small introductions to sections of Mishna Torah called a Koteret. In the introduction to Hilchos Talmud Torah he writes:
יש בכללן שתי מצוות עשה--(א) ללמוד תורה; (ב) לכבד מלמדיה ויודעיה. וביאור שתי מצוות אלו בפרקים אלו.
A Mitzvah to learn Torah and a Mitzvah to honor those who learn it and know it.
In the Minyan Hamitzvot Hakatzar , however, he lists, as the 11th positive commandment:
(לִלְמֹד תּוֹרָה וּלְלַמְּדָהּ, שֶׁנֶּאֱמָר: "וְשִׁנַּנְתָּם לְבָנֶיךָ" (דברים ו, ז.
To learn Torah and teach it, as is said: "And you shall teach your children" (Deut. 6:7)
Why does Rambam omit the obligation to teach Torah from the Koteret to Hilchos Talmud Torah, when he includes it in the associated Mitzvah listing? He could have easily included "וּלְלַמְּדָהּ" in the Koteret as well.