4-7 months the average, but babies do not learn to sit up all on their own. You need to help them! Prop them up in a boppy or hold them in your lap with as little support as possible.Sit them up in shopping carts and encourage them to hold on to the front for balance instead of leaning back.eport Abuse. 4-7 months the average, but babies do not learn to sit up all on their own. You need to help them! Prop them up in a boppy or hold them in your lap with as little support as possible. Sit them up in shopping carts and encourage them to hold on to the front for balance instead of leaning back.
He's fast become one of the most charming voices on the Internet. I must know: Who's the writer behind Karl the Fog? to wit: Karl The Fog Explains How He Got the Gig as San Francisco's Fog.
Robert William Fogel was an American economic historian and scientist, and winner of the 1993 Nobel Memorial Prize in Economic Sciences. As of his death, he was the Charles R. Walgreen Distinguished Service Professor of American Institutions and director of the Center for Population Economics (CPE) at the University of Chicago's Booth School of Business. He is best known as an advocate of new economic history â the use of quantitative methods in history.