For families with two or more descendants and low income
Regulations: Art. 14 Text Recast of the legal provisions of the Community of Madrid regarding taxes transferred by the State, approved by Legislative Decree 1/2010, of October 21.
10 percent of the amount resulting from reducing the full regional quota in the rest of the regional deductions applicable in the Community of Madrid and the part of state deductions that are applied to said full regional quota.
This operation will be carried out by subtracting from the amount of the full regional quota, box  of the declaration, the amounts entered in boxes  ,  ,  ,  ,  ,  ,  and  , as well as the one in box  , excluding from the latter the amount corresponding to this deduction and box  corresponding to the new deduction applicable to family units formed by tax residents in Member States of the European Union or the European Economic Area.
Requirements for applying the deduction
That the taxpayer has two or more descendants who generate in his favor the right to apply the corresponding minimum for descendants established in the regulations governing Personal Income Tax .
That the sum of the general and savings tax bases , sum of the boxes  and  of the declaration, does not exceed 24,000 euros .
To calculate the sum of the tax bases, the following will be added:
Those of taxpayers who have the right, for the same descendants, to the application of the corresponding minimum whether they file individually or jointly.
Those of the descendants themselves who give the right to the aforementioned minimum.