Across
1
System of ordered marks for measuring
3
Line crossing from corner to corner
5
Total distance around a shape
8
Rectangle with four equal sides
10
Proven mathematical statement
11
Exact correspondence on both sides
Down
2
Symbol representing unknown value
4
Comparison of two quantities
6
Line segment connecting two circle points
7
Difference between highest and lowest values
9
Parts per hundred
12
Math using letters for unknown values