Introducing Adding and Subtracting Negative Numbers

I have always found it difficult to tutor negative numbers adding and subtracting without saying, "two negatives make a positive". Then when I was at university I was taught a way to show negative numbers with + - signs like in science, as it is common that a child would be taught about positive and negative charges in science. Unfortunately this didn't work too well with a year 6 pupil I tutored. I then decided to adapt this method and put positive and negative signs onto some cubes, this way the pupil could physically see what was happening. The pupil much preferred 'hands on' methods anyway and found this easier to understand.

Therefore I thank the person who came up with the original idea which enabled me to adapt it to my pupils.