I have more than 20 in kindergarten. When I first started teaching almost 30 years ago, this wasn't an issue because kids were different. We didn't do so much inclusion and testing. Kindergarten was for socialization and some academics. It was also half day. The kids we get now are such a combination of abilities and manners, some aren't even toilet trained. As far as my older students, it's the same deal. Many abilities all mixed together with some major social issues. My first years of teaching were usually 25 to 32 in a class. Things are much different now thanks to No CHild Left Behind.
Charlotte
What you said is absolutely right, Charlotte, and I totally forgot about that. It's a shame that kids don't come to school prepared, even in kindergarten. When I was there, we were all 5 year olds that did a little academic learning, like learning how to write our names, learning the names of things, did lot's of art and a bit more, but we socialized, and learned to get along, and took a nap every day, and it was only half a day. And we were all toilet trained.

That is inexcusable.
Things are different now. And have been for quite some time. I was speaking with a woman at work the other day about the lack of work ethic of young people today, and why that is. It's a rare young person who is interested in working, and comes to work ready to work.
Interesting how kids go to school not prepared, teachers are expected to "raise" people's children for them, then when they get into the work force, they find out expectations are entirely different. Welcome to the real world.
Part of filling out an application to work for my company involves taking a math test. It's 20 questions, and has equations and "story problems", dealing with fractions, percentages, and general math. I apparently did it the fastest of any applicant, and was the only one to get 100% right. These are typical math situations that I run into every day.
When I'd give people the application to fill out later, many people would come back to me and say "I can't do that kind of math", or only answer a few questions, and leave the rest. There is no time limit, they get to use a calculator (although at the time, I couldn't), and have scratch paper.
Oh, and the company I work for has no debt, and has made a record profit every year for the last 5 years. Just not as much as XOM.