Across
1
Number greater than zero
4
Result of addition
5
Line touching circle at one point
7
Value that does not change
8
Middle value in an ordered dataset
9
Result of multiplication
10
Math using letters for unknown values
11
Lines that never intersect
12
Three-sided polygon
Down
1
Total distance around a shape
2
Split into equal parts
3
Steepness of a line
6
The number representing nothing
9
Number divisible only by 1 and itself
13
Closed shape with straight sides