DOYLESTOWN, Pa. (CBS) — William ‘Bill’ Grun loves to laugh. It’s his laughter that he loves to share with his students.

“I started to teach in September 1947 and I’ve never stopped,” he said.

At 98 years young, Grun’s now in his 72nd year of teaching.

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“It’s gift I feel. It’s a privilege that I’ve been given that I’m healthy enough to do it,” explained Grun.

He taught industrial arts at Abington schools. He retired in 1980 and went on to teach technology and mechanical drawing in Buckingham Township every Friday for the past 27 years at Holicong Middle School.

“I really enjoy the children at that age. They’re open to learning and by some cork, kids like me,” said Grun.

His middle school students liked him so much that after hearing about his heart attack last December, they visited visited him at his assisted living home in Doylestown with a surprise cake for his birthday.

They later serenaded him and other seniors at Wesley Enhanced Living in Doylestown with a concert.

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“I’m just really happy to get to see him,” said one of Grun’s students Veronica Hodgson. Students say what makes the concert so special is that is that Bill Grun usually sings for his students at Holicong Middle School.

“It was a way for us to give back everything he’s done for us and it felt nice to honor him in a certain way on his birthday,” said student Kiera Donnelly.

“They’re my kids. They’re what keeps me young,” expressed Grun.

He also offered advice that he learned from his own teacher at Frankford High School in Philadelphia.

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“Blessed is the man who has found his work and I found mine and so that’s what I say to young people, find something that you love and do it. Don’t exist in a job that you don’t like,” said Grun.