As all the models which Calcularis is based on (from Shalev&von Aster to Dehaene and Butterworth) determine, automating each number representation (magnitude, verbal, Arabic, number line) as well as automating to switch between these representations (called "Transcoding" according to Dehaene), is paramount in math skill development - and inhibited or at least delayed in children with dyscalculia.
These foundations are thus explicitly trained in Calcularis, e.g. through exercises, which ask to compare quantities; exercises, which ask to position numbers (both presented as quantities, numerically or verbally) on a number line; exercises for estimation; etc. But also exercises for transcoding, where e.g. a structured set (a quantity) is presented, and children need to provide the numeric representation.
All Calcularis exercises of the area "Number Processing" explicitly accentuate numeracy. But also e.g. addition and subtraction tasks are executed on or at least related to the number line, and thus implicitly also strengthen numeracy, in particular the understanding, that addition is increasing quantities or navigating right on the number line and subtraction is decreasing quantities and navigating left on the number line.
Indeed, several studies with Calcularis showed an increased number sense in children. In particular, they were able to significantly more accurately solve number line tasks, which is one of the strongest indicators for numeracy.
Eg. https://constructor.tech/research/calcularis-numerical-cognition or https://constructor.tech/research/arithmetic-skills-children.
An overview of the games and the skills they train can be found in the attached file here.