“No, Henry, you can’t do that,” said the teacher, pointing to Henry’s exercise book, where he had written:
“Sorry, sir<” said Henry. “What’s wrong? I checked it on my calculator and it seemed to work.
“Well, Henry, the answer is right, I guess,” the teacher admitted. “Though you should probably cancel the 9’s to get 
Explain the mistake to Henry. Then, find all the sums, with single non-zero digits in the first two fractions, that are correct.
Answers later.
More later,
Nalin Pithwa
Ref: Professor Ian Stewart’s Cabinet of Mathematical Curiosities.
