Subscribe now

BrainTwister #66: Easy times?

Can you solve this week’s logic puzzle? Plus our quick quiz and the answer to last week’s problem

By Phil Lloyd

26 March 2025

New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

Shutterstock/ktsdesign

#66 Easy times?

Set by Phil Lloyd

If you start with the number 185 and move the first digit to the end, you get 851. You get the same result when you multiply 185 by 4.6.

In a similar fashion, the number 15 can be multiplied by a number between 3 and 4 to move its first digit to the end. What number do you need to multiply by?

Can you find a 3-digit number, where the first digit is 1, that must be multiplied by 2.6 to achieve the same effect?

How about a 5-digit number that is multiplied…

Sign up to our weekly newsletter

Receive a weekly dose of discovery in your inbox! We'll also keep you up to date with New Scientist events and special offers.

Sign up

To continue reading, subscribe today with our introductory offers

Piano Exit Overlay Banner Mobile Piano Exit Overlay Banner Desktop