Kosinus is a dragon who so loves numbers that he is tempted to eat them. He is always in trouble as a result, and ends up a captive, secure behind a dragon lock. Solveig, his best friend, invariably comes to his rescue. But the keys of the lock are secreted in magical hideaways, and to recover them Solveig has to find the answers to a series of mathematical problems.
Kosinus, a dragon, loves numbers. He lives together with Solveig, close to her numbers factory. Solveig also delights in numbers. Kosinus has no idea of how old he is, as there were no numbers on the mountain where he grew up. He had never encountered human beings - or numbers - until the day Solveig came to study his mountain and carved some numbers in the rock. The two became close friends when she showed him all the numbers and taught him to count. It was then he realized how wonderful numbers can be and went back with her to her home and the numbers factory.
Kosinus is constantly in trouble, as he is so hooked on numbers that he can't help but gobble them up. He sees numbers everywhere, on clocks, on road signs and on price tags. He does his best not to eat them, but sometimes the temptation is simply too great. He just loves them! And that is his downfall, as so much can go wrong without numbers. Clocks don't show the right time and chocolate becomes too cheap. That is why the grown-ups insist on his leaving their numbers alone. Kosinus is locked up and is unable to return home.
Only Solveig can save him. Strong, brave and resourceful, she is prepared to do almost anything to save Kosinus when he is in danger. But she needs three keys to free her beloved dragon, and for each key is confronted by an obstacle which she can only surmount by solving a mathematical problem. She has to count, sort, make patterns and measure things. She is quite often helped by children - sometimes by children on the screen, at other times by children watching the programme. She finally reaches Kosinus, persuades him to spit out the number he has swallowed and to hand it back and apologize. They then fly home together and Solveig can continue her work at the numbers factory ... until the next time Kosinus gets into trouble.
Kosinus is played by an adult in costume. Solveig is played by Solveig Hareide, who both presents the programme and is the heroine. The series is produced for NRK Super by the Science Department of NRK Trøndelag in collaboration with, among others, the Department of Mathematical Sciences of the Norwegian University of Science and Technology (NTNU).
The series aims to interest viewers in the numbers, shapes and spaces that surround them.
The name 'Kosinus' derives from the mathematical expression for calculating the lengths of the sides of triangles. (Two definitions: 'For acute angles cosine may be defined as the relationship between the sides of a right-angled triangle' or 'The cosine of an angle is the relationship between the adjacent side and the hypotenuse').