Across
1
Closed shape with straight sides
4
Collection of distinct elements
5
Part of a circle's circumference
6
Lines that never intersect
7
Rectangle with four equal sides
9
Number that divides evenly into another
10
Mathematical rule or equation
11
The number representing nothing
Down
1
Number divisible only by 1 and itself
2
Middle value in an ordered dataset
3
Three-sided polygon
8
Line segment connecting two circle points
12
Comparison of two quantities