School of Hard Sums

The evening in with Annie and Chris was spent doing calculus. We were watching Dara O'Briain's School of Hard Sums and the last challange involved differentiation. Annie a got a pen and an envelope out and set about it. She ran out of envelope with still no answer but she's got a bigger piece of paper now and a determined look on her face.

We know how to have fun, after all Chris began the evening with a 6.5 mile run.