The instructions are attached to the resource. Basically the children need to use their knowledge of mental subtraction to order themselves into a line. This could also be used as an individual game where the children place the cards in order on the floor.
A great idea! I particularly like how the children are not only solving their own calculation, but also those of others playing the game. The 'silent' part is also an added bonus. An editable resource so I will be using this with every guided maths group. Thank you!