Across
1
Amount of space an object occupies
4
Part of a whole number
7
Number greater than zero
9
Result of multiplication
10
Part of a circle's circumference
11
Difference between highest and lowest values
13
The number representing nothing
Down
2
Rectangle with four equal sides
3
Number less than zero
5
Symbol representing unknown value
6
Rectangular array of numbers
8
Repeated addition
12
Collection of distinct elements