Bøger i Math Adventures serien

Oh, no: the evil Mister X has smashed an ancient tablet containing all the numbers of the world--and if Tommy and Tina can't mend it by midnight, every number will disappear forever! Are Tommy and Tina up to the mission? Fifth-graders can help them succeed by doing calculations to avoid traps, figuring out which footprints to follow, and solving puzzles to enter an enchanted tower.