Across
1
Reference line in a graph
3
Number divisible only by 1 and itself
4
Longest side of a right triangle
9
Symbol representing unknown value
13
Result of addition
Down
2
Steepness of a line
5
Rectangular array of numbers
6
Repeated addition
7
Sum divided by count
8
Result of multiplication
10
Number with digits after a point
11
Comparison of two quantities
12
Collection of distinct elements