Across
1
Symbol representing unknown value
3
Result of addition
4
Number divisible only by 1 and itself
7
Line crossing from corner to corner
9
Three-sided polygon
Down
2
Difference between highest and lowest values
3
Rectangle with four equal sides
5
Mathematical rule or equation
6
Corner point of a polygon
8
Line segment connecting two circle points
10
Round shape with all points equidistant