Across
1
The number representing nothing
3
Math using letters for unknown values
5
Divisible by two
6
Amount of space an object occupies
7
Mathematical rule or equation
9
Part of a circle's circumference
10
Closed shape with straight sides
11
Reference line in a graph
Down
2
Longest side of a right triangle
4
Difference between highest and lowest values
6
Symbol representing unknown value
8
Number with digits after a point