10. (3 points)

Find the smallest natural number that starts with the digit 3 and which, after erasing this digit, decreases by 25 times.
Answer: 3125

## Interregional Subject Olympiad KFU 2013-2014, MATHEMATICS 9th grade, 2nd variant, Internet round

The answer in each task should be an integer or a number written as a finite decimal. If the answer contains a fractional number, then when writing it, use a comma. All symbols (minus sign, comma, digits) should be entered without spaces. There is no need to indicate units of measurement.