Across
1
Difference between highest and lowest values
2
Part of a line with two endpoints
4
Number less than zero
5
Line crossing from corner to corner
6
Symbol representing unknown value
9
Middle value in an ordered dataset
13
U-shaped curve of a quadratic function
Down
2
Exact correspondence on both sides
3
Math using letters for unknown values
7
Part of a whole number
8
Part of a circle's circumference
10
The number representing nothing
11
Steepness of a line
12
Longest side of a right triangle