横向
1
Total distance around a shape
3
Closed shape with straight sides
5
Space between two intersecting lines
8
Number with digits after a point
9
Math using letters for unknown values
10
Difference between highest and lowest values
纵向
1
Lines that never intersect
2
Split into equal parts
3
U-shaped curve of a quadratic function
4
Proven mathematical statement
6
Repeated addition
7
Visual representation of data
11
The number representing nothing
12
Amount of space an object occupies
13
Divisible by two