Across
1
Math using letters for unknown values
5
Result of multiplication
6
Line crossing from corner to corner
7
Value that does not change
9
Rectangle with four equal sides
12
Distance from center to edge of circle
Down
2
U-shaped curve of a quadratic function
3
Reference line in a graph
4
The number representing nothing
8
Number with digits after a point
10
Mathematical rule or equation
11
System of ordered marks for measuring
13
Line segment connecting two circle points