The Maths Friend. New Teacher

The summer holidays are over, and Markus and Peeter must return to school. The boys are now in the second grade at Vaablase Primary School, and to their surprise, Peeter’s grandfather has been enlisted—at the principal’s request—to teach music and mathematics. Only he does not appear as Peeter’s grandfather, but as Aunt Laine from Võrumaa. For the role, a body of ultra-strong titanium fibre was created on a distant planet—an exact copy of the plump aunt whom the boys had lured to Peeter’s home planet.

As ‘Aunt Laine,’ Peeter’s grandfather finds himself in one comical scrape after another. Before long, the principal begins to suspect that neither Peeter nor Aunt Laine are quite ordinary humans…----------------------
Fifth book in the series of The Math's Fan. A humorous series that makes you love maths without even trying.