Across
1
Number with digits after a point
3
System of ordered marks for measuring
5
Symbol representing unknown value
8
The number representing nothing
10
Lines that never intersect
11
Power to which a number is raised
Down
1
Split into equal parts
2
Steepness of a line
3
Rectangle with four equal sides
4
Reference line in a graph
6
Number divisible only by 1 and itself
7
Visual representation of data
9
Line touching circle at one point
12
Sum divided by count