plus
2 + 899?
=901
1-0
=0
1-2-3-4-5-6-?-8
7
2:46
23
3x9
27
2 + 2
= 4
100-400
=300
5-10-15-?-25-30
20
1:20
20
2x20
40
190 + 110
= 300
289-288
10-20-30-?-50-60
40
3:9
3
9x9
81
420 + 420
= 840
2009-2008
=1
15-30-45-?-75
60
20:100
5
10x10
100
1k + 1k
98-34
=54
25-50-?-100
75
100:800
8
30x3
90