Across
1
The number representing nothing
4
Sum divided by count
5
Number divisible only by 1 and itself
8
Part of a whole number
10
Part of a line with two endpoints
12
Number with digits after a point
Down
2
Round shape with all points equidistant
3
Difference between highest and lowest values
5
Closed shape with straight sides
6
Result of raising a number to an exponent
7
U-shaped curve of a quadratic function
9
Single numeral from 0 to 9
11
Part of a circle's circumference