Find the unit’s digit of 61 × 62 × 63 × ... × 69.
Explanation:
This is a product of all the integers from 61 to 69.
In this product, there is one 5 (at units place of 65) and at least one even number (at units place of 62, 64, 66 or 68).
When 5 is multiplied with any even number, it always ends with 0. So, the unit’s digit is 0.
Also, when 0 is multiplied with any number, it always ends with 0. So, the unit’s digit is 0.
Hence, option (d).
» Your doubt will be displayed only after approval.
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.