横向
1
Repeated addition
3
The number representing nothing
5
System of ordered marks for measuring
6
Symbol representing unknown value
7
Round shape with all points equidistant
纵向
2
Number divisible only by 1 and itself
4
Part of a whole number
5
Exact correspondence on both sides
8
Math using letters for unknown values
9
Collection of distinct elements
10
Lines that never intersect