Radius and Per have a map to the hidden treasure of Viking Xaxon Yellowbearyd, but they must decode the numbered grid on the map.

Explores basic concepts of geometry.

King Arthur was a good ruler, but in this math adventure he needs a good ruler. Geometry is explained with humor in SIR CUMFERENCE AND THE FIRST ROUND TABLE, making it fun and accessible for beginners. What would you do if the neighboring kingdom were threatening war? Naturally, you'd call your strongest and bravest knights together to come up with a solution. But when your conference table causes more problems than the threat of your enemy, you need...

While riding through the forests of Angleland, cousins Per and Radius realize they are lost and are desperate for a map to guide them home. Soon they come across a mysterious house in the hills. Inside they find a map to a treasure belonging to Xaxon Yellowbearyd, the fiercest Viking warrior of his time. Per and Radius must decode the strange numbered grid on the map, while trying to steer clear of the pack of bungling bandits who are on their tail....

When young Per visits her uncle Sir Cumference and his family, she learns how to play the game, "Inners and Edges." After she finds a clue linking the game to the mysterious castle on the island of Immeter, she must figure out how to find the perimeter and area of a circle to unlock the island's secret. Math skills taught include finding the area and perimeter of a rectangle and a circle. Introduces an underlying concept of calculus -- using straight...