Across
1
Number divisible only by 1 and itself
4
Line touching circle at one point
5
Single numeral from 0 to 9
7
System of ordered marks for measuring
8
Symbol representing unknown value
10
Sum divided by count
11
Round shape with all points equidistant
Down
2
Collection of distinct elements
3
Distance from center to edge of circle
6
Total distance around a shape
9
Part of a line with two endpoints