Those are standard scores, Alexander.
You do 10 little tasks and get raw scores (eg they got 5 points on the "block design" task).
These are then converted into scaled scores (on the WISC) which run from 1-19 and are age normed. For example if your child was 9y 2m old you look up what the raw score of 5 on block design converts to, eg a scaled score of 4 which is low. This allows us to use the same test on a wide age range as it compares age groups. If your child was only 8 and got 5 points on block design, they'll get a higher scaled score than if they were 15 and got 5 points.
The scaled scores are them put together into clusters which measure skills which are often related - eg verbally based tasks, spatially based tasks. This then gives you 3 scaled scores which are added and converted into a cluster score which is a standard score - on a bell curve distribution with average range (usually) of between 85-115 . You can only calculate clusters if there isn't a huge gap between your scaled scores. In other words if your scaled scores are 4, 5, 5 it's fine, but if they are 4, 5, 12 it's not ok and then you need to look at the possible reasons for the gap in results.
The full scale score takes all the clusters (if there is less than 23 points between lowest and highest cluster) to give an overall score which is an attempt to reflect the likelihood of learning facility in someone with the scores provided. It's by no means an exact science and can be affected very significantly by anxiety in particular - or attention, work speed, illness, etc.