横向
1
Round shape with all points equidistant
4
Reference line in a graph
6
The number representing nothing
7
Number less than zero
8
Collection of distinct elements
10
Split into equal parts
12
Repeated addition
纵向
2
Result of multiplication
3
Number greater than zero
5
Lines that never intersect
9
Middle value in an ordered dataset
11
Part of a line with two endpoints
13
Result of raising a number to an exponent