We have all become a bit lazy these days with mental arithmetic. After all, it’s much easier to put the numbers into a calculator, or your phone, and be 100% sure you got the correct answer! But doing your sums in your head might actually be good for you, as it keeps those neurons in your brain firing. Take the test to see how well you do without a calculator.

Click HERE to reveal the answer!

The correct answer is... 14!

So how did you do? Comment below and click SHARE to challenge friends and family!