横向
1
Number divisible only by 1 and itself
3
Math using letters for unknown values
5
Distance from center to edge of circle
6
Middle value in an ordered dataset
9
U-shaped curve of a quadratic function
纵向
1
Lines that never intersect
2
System of ordered marks for measuring
4
Single numeral from 0 to 9
7
Steepness of a line
8
Part of a line with two endpoints