Across
1
Symbol representing unknown value
3
Part of a line with two endpoints
7
Rectangle with four equal sides
8
Single numeral from 0 to 9
11
Power to which a number is raised
Down
2
Closed shape with straight sides
3
Exact correspondence on both sides
4
The number representing nothing
5
Divisible by two
6
Repeated addition
9
Total distance around a shape
10
Number with digits after a point