Gohd
Improved Answer:-
Numbers were once formed on a tally stick whereas 4 notches would indicate 4 and 4 notches with a line through them would indicate 5 and so on.
There are 504 such numbers.
100,000
823543
Square numbers.
6
100000000000 kantutan
There are 504 such numbers.
100,000
The question to help my son with his homework is: How many unique numbers can be formed by combining three sets of three digital decimal numbers
840
823543
Square numbers.
There are 60480 numbers.
6
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
9999
There are 4^6 = 4096 such numbers.