Since the numbers begin with 123, they all contain a 3. As a result, they all "contain 3 or 7". So the remaining 4 digits can be any digits and this gives 104 = 10,000 such numbers.
A crore has 7 digits.
7
180
There are 192.
Since the numbers begin with 123, they all contain a 3. As a result, they all "contain 3 or 7". So the remaining 4 digits can be any digits and this gives 104 = 10,000 such numbers.
A crore has 7 digits.
7
36 of them.
There are 13 such numbers.
8.
180
There are 192.
120 There are 6 digits in total. The numbers with 3 digits, with all digits distinct from each other, are the permutations of the 6 digits taken 3 at a time, and therefore there are 6*5*4 = 120 of them.
7 two-digit numbers.
252 of them.
5,050