Across
1
Line crossing from corner to corner
2
Exact correspondence on both sides
4
Proven mathematical statement
5
Parts per hundred
7
Part of a circle's circumference
10
The number representing nothing
11
Mathematical rule or equation
Down
2
Steepness of a line
3
Value that does not change
6
Number divisible only by 1 and itself
7
Sum divided by count
8
Total distance around a shape
9
Middle value in an ordered dataset