横向
1
Comparison of two quantities
5
Math using letters for unknown values
6
Distance from center to edge of circle
7
Mathematical statement of equality
11
Rectangular array of numbers
13
Proven mathematical statement
纵向
2
U-shaped curve of a quadratic function
3
The number representing nothing
4
Collection of distinct elements
8
Sum divided by count
9
Closed shape with straight sides
10
Line touching circle at one point
12
Steepness of a line