A number's persistence is the number of steps required to
reduce it to a single digit by multiplying all its digits to
obtain a second number, then multiplying all the digits of
that number to obtain a third number, and so on until a one-
digit number is obtained. For example, 77 has a persistence
of four because it requires four steps to reduce it to one
digit: 77-49-36-18-8. The smallest number of persistence
one is 10, the smallest of persistence two is 25, the smallest
of persistence three is 39, and the smaller of persistence
four is 77. What is the smallest number of persistence five?

It's annoying that you call it a simple puzzle

Ans: 679

6*7*9 equals 378
3*7*8 equals 168
1*6*8 equals 48
4*8 equals 32
3*2 equals 6

I dey cum

Let me try,