Across
1
Round shape with all points equidistant
5
Single numeral from 0 to 9
6
Split into equal parts
7
Part of a whole number
9
U-shaped curve of a quadratic function
11
Total distance around a shape
Down
2
Part of a circle's circumference
3
Number greater than zero
4
The number representing nothing
8
Part of a line with two endpoints
10
Collection of distinct elements