Across
1
Part of a line with two endpoints
4
Math using letters for unknown values
5
Steepness of a line
7
Single numeral from 0 to 9
8
Sum divided by count
Down
2
Total distance around a shape
3
Result of addition
5
System of ordered marks for measuring
6
The number representing nothing
7
Line crossing from corner to corner
9
Number with digits after a point