横向
1
Difference between highest and lowest values
5
Number with digits after a point
6
Exact correspondence on both sides
8
The number representing nothing
9
Sum divided by count
13
Line crossing from corner to corner
纵向
2
Mathematical rule or equation
3
Number less than zero
4
Collection of distinct elements
7
Lines that never intersect
10
Closed shape with straight sides
11
Parts per hundred
12
Round shape with all points equidistant