Across
1
Closed shape with straight sides
4
Symbol representing unknown value
8
Mathematical rule or equation
9
Round shape with all points equidistant
10
Middle value in an ordered dataset
11
Space between two intersecting lines
12
Repeated addition
Down
1
Total distance around a shape
2
System of ordered marks for measuring
3
Divisible by two
5
The number representing nothing
6
Corner point of a polygon
7
Lines that never intersect