Using all the digits 1, 2, 3, 0, 7, 9, six digit numbers are to be formed.
∴ Excluding digit 0, one of the five digits can be placed at the first place in 5P1 ways
Now, remaining 5 digits (including 0) can be arranged in remaining 5 places in 5P5 ways.
∴ Total permutations for six digit numbers
= 5P1 × 5P5
= 5 × 5!
= 5 × 120
= 600
Hence, 600 numbers of 6 digit can be formed.