"Does that keep me connected in the same way that it would if I could get in my car and drive to Target? No, I can't do that," Obama said with a laugh. "I'm working on that but I can't."
The first lady says while she is away, homework duty has been added to the presidential agenda.
"He's supposed to be," checking homework, Obama said of the president. "I'm going to call tonight and see what's happening. Last night he said he was on top of it – we'll see."
The first lady noted that since their daughters are "pretty self-sufficient" when it comes to assignments, they do not really need a lot of parental assistance.
"He can handle it. Really. Even the President of the United States can handle figuring out whether someone put their writing assignment in their bookbag," she said with a laugh.
Obama's first day in Mexico was a mixture of culture, policy and song and dance.
At the Escuela Siete de Enero, an elementary school in a low-income neighborhood of Mexico City, the students screamed with delight when the first lady stepped out of her vehicle.
"Mi-che-elle," the children chanted loudly. There were large sign covered with the students' handprints that read, "Bienvenida Sra. Obama" or "Welcome Mrs. Obama."
The first lady was given flowers and kisses on the cheek from a young female student.
While she is not here in Mexico specifically touting her "Let's Move!" campaign, the message is never far away. She observed a physical education class and even joined in for some drills, a follow the leader-call and respond dance.
The students rewarded the first lady with a large conch shell that they had used in the dance routine.
"That was beautiful. I loved the singing, I loved the dancing," Obama said at the conclusion. "I loved to see you all moving and exercising. So just know today you made your country proud. Everyone here today got to see the best of Mexico's young people."
Obama said that of all the things she does abroad, what she likes best is getting to see smart intelligent students.
The first lady did her version of a ropeline – complete hugs instead of handshakes.
Earlier today, Obama toured the Museo Nacional de Antropologia with Margarita Zavala. The museum holds the largest collection of ancient Mexican artifacts in the world.
The first ladies were treated to a performance by the National Program for the Promotion of Music, which encourages artistic expression in young Mexican children. The National Children's chorus, which is made up of kids from around the country, including some with special needs, also performed.
Obama's trip was the kickoff to her international agenda, which aides said will focus on engaging the world's youth in conjunction with her husband's broader vision of global engagement. Nearly half the population of Mexico is under the age of 25.
She and Zavala discussed in their private meeting earlier today how the two nations can work together on this issue.
"Mrs Obama and Mrs. Zavala underscored the importance of engaging families and communities in tackling the challenges facing young people in both countries as a key to helping build a better future for the United States and Mexico," a statement from the first lady's office read.