What is one reason that the number of children working in factories increased in the late 1800s?

A lot of children worked to make money for their families or themselves. They worked in anything from railroad to textile industries with the same pay as adults (but don't take my word on the pay). During the 1800's and the Industrial Revolution,a lot of people were very poor,so the more people in the family that worked,the more money,which lead to a greater standard of living 

Hope this helped

Your answer would be a , i hope you do very well

February 1848 is when it was added. if that's what you were asking