This maths puzzle is just what you need to melt your head this afternoon

The maths quiz will mess with your head...

We'll be honest, we spent much of the weekend getting more than a little bit 'refreshed,' so we're not at our sharpest. This maths puzzle is not helping. BBC's Today show on Radio 4 decided that this particular Monday was the perfect time to launch an excellent new mathematical puzzle feature. It's very, very tough. The BBC say they won't be revealing the definitive answer until 6am on Tuesday morning, so it could plague you for the next 24 hours. Here goes....

Take the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9. Insert the fewest numbers of plusses and minuses wherever you want to get to a grand total of 100. You must keep the numbers in that order. However, you can combine numbers as long as they stay in sequence (for example 4, 5 can become 45). The BBC (helpfully) gave an example of how to complete it using six plusses and minuses: 1 + 2 + 34 - 5 + 67 - 8 + 9 = 100, but it can be done using fewer plusses and minuses.  Have a go.

The definitive answer will be known first thing on Tuesday morning. Good luck.