Across
1
Total distance around a shape
5
Result of raising a number to an exponent
6
Power to which a number is raised
7
Reference line in a graph
10
Exact correspondence on both sides
11
Collection of distinct elements
13
Sum divided by count
Down
2
Middle value in an ordered dataset
3
Rectangle with four equal sides
4
Repeated addition
5
Number greater than zero
8
Rectangular array of numbers
9
Comparison of two quantities
12
The number representing nothing