Across
1
Number less than zero
6
Sum divided by count
7
Lines that never intersect
8
Exact correspondence on both sides
10
Line crossing from corner to corner
11
Distance from center to edge of circle
12
Difference between highest and lowest values
Down
2
Space between two intersecting lines
3
Symbol representing unknown value
4
Mathematical statement of equality
5
Middle value in an ordered dataset
9
System of ordered marks for measuring
13
Result of multiplication