What mathematical symbol can be placed between 5 and 9, to get a number greater than 5 and smaller than 9?

Hard:

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

Super Hard:

“Hey Greg!” crackled the Police Band. “We got a traffic situation out here…and it looks like the truck was positively ID-ed as the getaway vehicle in last week’s Ninja Monkey bank heist.”
As the Police officer Greg Jones roared down the highway, he reviewed the facts of the bank heist case. Stealing a record of 1 million Dollars just as the bank was opening, 5 robbers dressed as monkey ninjas had gotten clean away from the Bank, taking the highway heading East and disappearing. Their only clue was a description of the getaway vehicle: a solid black truck with a white racing stripe in the middle—-which looked like exactly like the truck Greg’s friend, Jack Wilson, was giving a ticket to.
“I caught him running the red light,” Jack explained to Greg. “That’s when I noticed the racing stripe.”
The driver, a big burly brute of a man, was practically snarling. “Just give me the ticket and scram, see? This isn’t the truck you’re looking for…I was doing deliveries at the time of the robbery! You can check with my boss.”
He suddenly paused, scratching his massive chin. “On second thought…while on the highway, I passed a truck that looked exactly like mine, heading the opposite direction. I couldn’t see the drivers clearly ’cause the sun was in my eyes, but I did think at the time that their faces looked kinda funny—-like they were wearing masks or something. Would that be any help?”
Without looking up from his note-taking, Greg said, “Very much! Now can you please go with us to the station for questioning?”

Why is Greg bringing the man in for questioning?

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