Across
1
U-shaped curve of a quadratic function
5
System of ordered marks for measuring
6
Lines that never intersect
7
Result of addition
12
Single numeral from 0 to 9
Down
2
Number less than zero
3
Part of a circle's circumference
4
Distance from center to edge of circle
8
Line segment connecting two circle points
9
Repeated addition
10
Mathematical rule or equation
11
Space between two intersecting lines