How many digits are required to write first 250 natural numbers?

Single digit numbers are from 1 to 9 so in that total digits used = 9. From 10 to 99.there are 90 numbers of 2 digits , so here digit used = 90 x 2 = 180 From 100 to 250 = 3 x151 = 453 (as all are of 3 digit number). So number of digits required to first 250 natural number = 9 + 180 + 453 = 642

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