The Brilliant Problem of the Day Podcast

This episode of the podcast is sponsored by brilliant. Go check out brilliant dot org slash m p p for a 20 % discount on your premium subscription with the link in the description below. More about natural numbers. What in number theory was to take the numbers one times two times, three times four, five and figure out what's the last digit of this? We stop at nine. So multiply all the numbers one up to nine. What's the lastdigit? I want you to tell me how you figured it out. Just consent.