# Add new comment

Was vaccinating vulnerable people first a good choice? Hindsight allows us to assess this question.

A game you're almost certain to lose...

What are the challenges of communicating from the frontiers of mathematical research, and why should we be doing it?

Celebrate Pi Day with the stars of our podcast,

*Maths on the move*!Maths meets politics as early career mathematicians present their work at the Houses of Parliament.

B=8, D=6, E=5, F=4, H=2

1. A and C= 1 and 3; G=7; I=9

2. A and C= 1 and 9; G and I = 3 and 7

3. A and C= 7 and 9; G=3; I=1

183654729

381654729

189654327

189654723

981654327

981654723

789654321

987654321

These 8 numbers satisfy all the conditions except for divisibility by 7.

Is there a way to get the correct answer without checking each number individually?