Across
1
The number representing nothing
3
Result of addition
4
Number that divides evenly into another
5
Divisible by two
6
Symbol representing unknown value
11
Rectangular array of numbers
12
Longest side of a right triangle
Down
2
Amount of space an object occupies
4
Mathematical rule or equation
7
Single numeral from 0 to 9
8
Part of a line with two endpoints
9
Part of a circle's circumference
10
Rectangle with four equal sides