横向
1
Part of a line with two endpoints
3
U-shaped curve of a quadratic function
5
Middle value in an ordered dataset
6
Line touching circle at one point
8
Difference between highest and lowest values
纵向
2
Number less than zero
4
Single numeral from 0 to 9
7
Amount of space an object occupies
8
Distance from center to edge of circle
9
Proven mathematical statement