横向
1
Repeated addition
5
Part of a circle's circumference
7
Corner point of a polygon
8
Lines that never intersect
9
The number representing nothing
10
Reference line in a graph
纵向
2
System of ordered marks for measuring
3
Number greater than zero
4
Exact correspondence on both sides
6
Three-sided polygon
11
Collection of distinct elements
12
Symbol representing unknown value
13
Mathematical rule or equation