We learnt how to add and subtract 1 digit positive and 1 digit negative numbers.
Cupman showed us his garden where he was counting lumps of earth (1).
One day he went into the garden and found a hole (-1).
He filled the hole with a lump of earth to make the ground flat (0).
When we were adding we had to fill in the holes with lumps of earth using our 1 and -1 cards.
When we were subtracting we had to make the level ground 0, into a lump and a hole 1, -1 so that we could work out the Maths Story.
Can you teach someone how to do it?