Our home has several rooms which have textured (small bumps) walls. We would like a simple, smooth surface before we repaint. Is there a easy way to achieve this?

 

No


...no easy way, sorry


But there are ways
You'll probably use a combination of them, depending on what you have, and what works for your specific project

Start off scraping with nice wide scrapers
get as much as you can off
You may be left with tiny little holes, don't worry about that now
(it's easier to fill holes than make bumps smooth later)

Then go to sanding
Even if most of the texture comes off, you'll still want to sand before the next step
But I suspect you'll need to really sand with some power sanders
Knock down anything that's left or that you can

Then skim coat
(heads up, depending on what you have left after removal, you may need to prime before this step)
Using "taping knives" (big putty knives) spread layers of joint compound all over the affected areas
You might end up with a thin layer over the whole area, that's a skim coat
This must be sanded smooth, and it may take several layers before you have an acceptable surface

Then prime
The whole are will need a coat of good quality latex primer
(Tip: At this point, some areas you didn't quite sand smooth may show up, fix them now with some j/c and sanding, then spot prime)

Then you'll be ready to paint

The alternative would be to re-rock the room (new sheetrock)