It is given that leading number cannot be 0 and 8 . So, choices are :
[ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 9 ] i.e 8 choices.
Now, choices of other six digits are [ 0, 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8, 9 ] i.e 10 choices.
So, number of seven digits with given constraint is :
N = 8×10×10×10×10×10×10
N = 8000000
Therefore, seven-digit numbers with given constrain are 8000000.
Hence, this is the required solution.
