Across
1
Math using letters for unknown values
4
Collection of distinct elements
5
Number greater than zero
8
Number less than zero
10
Number divisible only by 1 and itself
11
Longest side of a right triangle
12
Result of addition
13
Total distance around a shape
Down
2
Mathematical rule or equation
3
Line touching circle at one point
4
Part of a line with two endpoints
6
Single numeral from 0 to 9
7
Three-sided polygon
9
Parts per hundred