The first was in the 2900 Block of Centreville Road on Friday at about 12:23 a.m.
A man wearing a mask and gloves entered a business and displayed a handgun to an employee. The victim handed over cash and the suspect fled. The victim did not require medical attention, police said.
The second took place at the Clocktower Shopping Center in the 2400 block of Centreville Road about 11 p.m. Friday.
Police said a man entered a business, displayed a handgun to an employee and demanded money. The suspect took cash and fled. The victim did not require medical attention. The suspect, described as 5 foot 9 inches, about 150 pounds, was wearing a ski mask, dark clothing and boots.
In other crime news:
UNLAWFUL ENTRY, 12000 block of Greywing Square, July 19. A property manager reported an unknown person entered a vacant apartment. Nothing was taken.
UNLAWFUL ENTRY/DESTRUCTION OF PROPERTY, 11300 block of Stonehouse Place, July 20. A resident reported several juveniles entered his backyard and damaged property.
2300 block of Freetown Court, wallet from vehicle.
Green Range Drive/Antiqua Court, property from vehicle.
12000 block of Greywing Square, license plate from vehicle.
2300 block of Hunters Woods Plaza, merchandise from business.
13100 block of Parcher Avenue, merchandise from business.
11600 block of Tori Glen Court, property from vehicle.
9100 block of Weant Drive, property from residence.