Question
How many 8-digit numbers are there in all?
✓
Answer
There are 10 digits i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
We cannot use ‘0’ at the place having the highest place value in 8 digit numbers.
So, we can use only 9 digits at the place having the highest place value in 8 digit numbers.
Also, we can use 10 digits at the remaining places in 8 digit numbers So, total numbers of 8-digit
numbers = 9 × 10 × 10 × 10 × 10 × 10 × 10 × 10 = 90000000
We cannot use ‘0’ at the place having the highest place value in 8 digit numbers.
So, we can use only 9 digits at the place having the highest place value in 8 digit numbers.
Also, we can use 10 digits at the remaining places in 8 digit numbers So, total numbers of 8-digit
numbers = 9 × 10 × 10 × 10 × 10 × 10 × 10 × 10 = 90000000
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