1,
989*112=110768
1107-1008(9*112)=99
996-896(8*112)=100
1008-1008(9*112)=0
2,
9999 9999 9999 9/7=1428 5714 2857 1.2
5555 5555 5555 5/7=0793 6507 9365 0.5
5x 0000 0000 0000 2
2...6*7=42
6...8*7=56
4...2*7=14
8...4*7=28
7...1*7=07
9...7*7=49
5...5*7=35
6...8*7=56
4...2*7=14
8...4*7=28
7...1*7=07
9...7*7=49
5...5*7=35
75714285714286*7=53 0000 0000 0000 2
（ ）内数字是3