1256
1256 ÷ 2 = 628, remainder is 0
628 ÷ 2 = 314, remainder is 0
314 ÷ 2 = 157, remainder is 0
157 ÷ 2 = 78, remainder is 1
78 ÷ 2 = 39, remainder is 0
39 ÷ 2 = 19, remainder is 1
19 ÷ 2 = 9, remainder is 1
9 ÷ 2 = 4, remainder is 1
4 ÷ 2 = 2, remainder is 0
2 ÷ 2 = 1, remainder is 0
1 ÷ 2 = 0, remainder is 1
So, 125610 = 100111010002.