Flight Instructor with student reported an NMAC while practicing maneuvers. Flight Instructor took evasive action to avoid a possible collision.

Narrative

While on a training flight; my student and I were in the 'practice area' south of Joe Pool Lake; just under or outside of the DFW Class B shelf. While pointing out a landmark to my student; he caught the traffic conflict out of the corner of his eye and alerted me to it. There was an Aircraft Y a few hundred feet at our 3 o'clock; same altitude; pointed directly at us. I took the controls and made an evasive maneuver. As the other aircraft turned away; I was able to read the tail number and called on the local practice area frequency to see if they were up; and got no reply. I reviewed the ADSB tracks to see the big picture; and it looked like the conflicting aircraft had turned right directly on to a collision course with us. Our aircraft was not equipped with ADS-B in or any kind of traffic awareness system. The other aircraft belonged to our flight school and I had flown it before; and I knew that it was equipped with a Garmin 650 with ADS-B traffic. I believe I got fixated on trying to instruct the student and temporarily neglected to scan for traffic while doing so.