Across
1
Proven mathematical statement
5
Steepness of a line
6
Symbol representing unknown value
7
Exact correspondence on both sides
Down
2
Closed shape with straight sides
3
Single numeral from 0 to 9
4
The number representing nothing
5
Part of a line with two endpoints
8
U-shaped curve of a quadratic function
9
Repeated addition
10
Reference line in a graph