Across
1
Single numeral from 0 to 9
2
Math using letters for unknown values
3
Number divisible only by 1 and itself
7
Longest side of a right triangle
8
Round shape with all points equidistant
9
Lines that never intersect
Down
2
Sum divided by count
4
Result of multiplication
5
Line segment connecting two circle points
6
Power to which a number is raised