In 7k7k, k k÷ 1 = k = 6 19k.

6 of 09K in 66÷ 1 = 6 = 665438+3366

Because the origin of the number is always ÷ 1, 1=6 19k's 1.

The formula can be reversed.

6+ 1+9+k=6 19k

Although this formula is not valid, I really can't figure it out, I hope I can understand it.