Across
1
Distance from center to edge of circle
4
Math using letters for unknown values
6
Proven mathematical statement
7
Line touching circle at one point
10
Difference between highest and lowest values
11
Reference line in a graph
12
Number divisible only by 1 and itself
13
Single numeral from 0 to 9
Down
2
Exact correspondence on both sides
3
Mathematical rule or equation
5
Number with digits after a point
8
Longest side of a right triangle
9
Part of a whole number