I would like to know if there is a way to track a cell phone by the phone number, I want to see where my kids go, I don't want them to know I am tracking them. So is there a software that allows me to do this

Check with your cellular provider: some have GPS features whereby you can go online to see where the phone is.

It is available on some models, on a lot of the cheaper phones it is not.
And of course you have to pay more for the phone services that provide that.

And I would say that while checking and making sure our children are safe, if there is such a issue that you need to do this, there is a bigger problem that needs to be addressed