Across
1
Exact correspondence on both sides
2
Line crossing from corner to corner
3
Space between two intersecting lines
6
Number with digits after a point
7
Symbol representing unknown value
9
Lines that never intersect
Down
1
Result of addition
2
Single numeral from 0 to 9
4
Math using letters for unknown values
5
Repeated addition
8
System of ordered marks for measuring
10
Round shape with all points equidistant
11
Longest side of a right triangle