f
i
r
s
t
n
u
m
b
e
r
s
e
c
o
n
d
n
u
m
b
e
r
1
2
3
4
×
4
3
2
1
1
2
3
4
2
4
6
8
0
3
7
0
2
0
0
+
4
9
3
6
0
0
0
5
3
3
2
1
1
4