Image copyright Facebook/Marion Ohio Police Image caption Lt BJ Gruber (right) went above and beyond the call of duty when he answered this appeal for help (left) from Lena Draper, 10

Every child knows when you are in trouble, you call the cops.

But it is fair to say, no police officer expects that trouble to be related to the complexities of a 10-year-old's maths homework.

Yet when faced with just such an issue, one brave officer in Marion, Ohio, stepped up to the mark.

Lena Draper decided to use Facebook to get in touch with her local police force, sending them an appeal for help at the weekend.

"I am having trouble with my homework. Could you help me?" she asked.

"What's up?" asked officer BJ Gruber, who told the BBC he was hoping "for something in the realm of history".

Unfortunately for him it was maths, with the added complication of a few brackets.

Undeterred, Lt Gruber threw himself into the challenge.

Image copyright Facebook Image caption Unfortunately, Lt Gruber's second answer was less correct

"I felt pretty confident with my answers on both questions and perhaps that worked against me with the second equation," Lt Gruber admitted.

Indeed, more than a few people have pointed out the answer he gave to the second, more complicated question, was incorrect - but the Police Department in Marion, Ohio, are still seeing the episode as a win.

"We are nailing our goals of increasing trust, transparency & being approachable. Still a work in product on the math skills," the force wrote on its Twitter page after Lena's mum Molly uploaded screenshots of the conversation to Facebook.

The post has now been liked more than 2,300 times.

"We really hope that are are not flooded with homework requests... so far, so good," Lt Gruber said.

"We really see this not different that a child walking up to an officer on the street and asking for help. This is just a 21st Century version of that interaction. We do however encourage kids to communicate with parents, teachers, siblings and fellow students before asking us."

As for Lena, she knows she can't always rely on the police to help her with her homework. But she does have a backup plan.

"Well, I'd call Ghostbusters then," she told Inside Edition.