The math is simple for Norland fans:

Roberts + basketball = success.

Since 2006, the Vikings’ boys’ and girls’ basketball programs have evenly combined to win four state titles, and there has been a Roberts on three of those teams.

Then again, that stands to reason since there have been nine Roberts — including five girls — playing basketball for Norland in the past decade.

On Friday at 11:30 a.m., two Roberts girls will try to get one step closer to another championship as Norland (24-6) plays Winter Haven (19-8) in a Class 6A state semifinal in Lakeland. The winner plays either Pensacola or Orlando Edgewater for the title on Saturday at 1:35 p.m.

“The Roberts family has been around Norland basketball for years,” Vikings coach Carla Harris-Curry said. “It’s in their blood.”

The Roberts tradition began on the girls’ side with Clecia, a 2004 graduate, and her sisters Cleniece and Cleandra. Their cousins — Nia and Kayla — are current members of Norland’s team.

The Roberts boys include Cleveland, who graduated in 2005; Alton, who won state as a reserve in 2008 and is now a 6-2 freshman guard for Santa Fe College in Gainesville; Cleon, a 6-5 senior wing and the star of the current Norland team; and Dalvin, a 6-1 sophomore starting point guard for the Vikings.

The family also includes uncle William Roberts, an offensive lineman for Carol City and Ohio State who went on to win two Super Bowls for the New York Giants in the late ’80s and early ’90s.

When it comes to basketball, though, Cleniece, a 6-foot senior starting forward for Bethune-Cookman, was the first of the Roberts girls to play in college.

Cleandra, a 6-foot sophomore forward, is sixth on Long Island University’s current scoring chart and was the first Roberts girl to win a state title, getting rings in 2009 and 2010.

Nia, a 5-11 junior center, was a freshman starter on that 2010 Norland team and is hoping to tie Cleandra this weekend by winning her second state title.

“Having my last name is an honor,” said Nia, who leads Norland in points (12.0), rebounds (9.1), steals (3.0) and blocks (1.2).

Kayla, a 6-foot sophomore forward, is averaging 7.8 points, 7.1 rebounds and 2.5 steals.

Nia said her little sister “wasn’t mature” last season, when Norland was eliminated from the playoffs in a 63-52 regional-final loss to Titusville.

It’s an opinion Kayla shares.

“I let my teammates down, and I let my sister down,” Kayla said. “I’m much more serious about basketball this season.”

Norland assistant coach Kent Forbes said Kayla has the potential to be the best of the Roberts girls, calling her talent “scary.”

Harris-Curry said the sisters are college prospects.

Both will need to play well if Norland is to have a strong shot at beating Winter Haven, which has made it to a state title game five times in the past six years, winning twice (’05, ’07).

Meanwhile, the Vikings boys and coach Lawton Williams are three wins from their third title since 2006.

Williams would love to see Cleon — a Georgia Southern recruit and the player the coach said is the best of the Roberts boys — end his prep career on top.

“Cleon needs to win state this year,” Williams said. “He needs to stop wearing his sister’s [state title] jacket and get one of his own.”