Number 7 has 1 digit as 7, 70 has 1 digit as 7. How many numbers between 100 and 1000 which have at least one 7 as a digit?

Answers (1)
A admin

each 10 has 1, 7

1000-10 = 900 will have 900/10 = 90 sevens

170 till 179 will have 10 additional 10 sevens. so will 270-279 and so on, that will make 10 x 9 = 90 sevens

700 till 799 will have additional 100 sevens

so total 90 + 90 + 100 = 280 sevens.

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