Across
1
Single numeral from 0 to 9
3
Power to which a number is raised
8
Closed shape with straight sides
9
Number divisible only by 1 and itself
10
Exact correspondence on both sides
11
Math using letters for unknown values
Down
2
Collection of distinct elements
4
Lines that never intersect
5
Total distance around a shape
6
Repeated addition
7
Sum divided by count
12
Reference line in a graph