By Jeff Rossen and Jovanna Billington, TODAY

(NBC News) - As parents, we drill it into our kids: "If there's ever an emergency and you need help, call 911." They learn about it in school, too.

"This should be the very first thing that a child learns when they know how to speak: where they live, their names, and what to do in an event of an emergency," Sgt. Tony Montanari from the Nutley, New Jersey police department told TODAY national investigative correspondent Jeff Rossen.

It's just three little numbers. We assume they'll remember and know what to do. But will they?

As an experiment, the Rossen Reports team set up cameras in a suburban home where real moms asked their own kids to demonstrate what they would do in an emergency. Rossen and Montanari watched on a monitor.

The results were revealing: Out of all the kids in the experiment, only one knew exactly what to do.

It's important to remember that not all emergencies may happen at home: Kids need to learn how to use smartphones and access the keypad.

Another important tip: Teach your kids to always look at their surroundings. If they call 911, they need to be able to describe what's around them, read street signs, describe the house. That way emergency teams get to you even faster.