The numerical constraint block is found in the Number section of the Data Statements drawer of the Blawx toolbox.
The numerical constraint block is used to specify that a numerical value must be in a given range.
The numerical constraint block is a statement, and can be stacked with other statements.
It requires two internal connectors, both of which must be variables or numbers.
It allows the user to choose the restriction to be applied to the left input, relative to the right input, either "less than", "greater than", "less than or the same value as", or "greater than or the same value as".
The numerical constraint block is a very powerful tool when dealing with numbers that are constrainted to be greater, equal to, or less than other numbers.
If a person at least 16 must pay taxes, and a person at least 18 may vote, then we know the age of a person who is required to pay taxes and cannot vote is at least 16 and less than 18. That is a numerical constraint that can be calculated by combining two other numerical constraints.
Through the numerical constrain block, Blawx allows you to express those sorts of rules, and get answers that are expressed as a range like "16 >= Age < 18".
There is no numerical constraint for "the same value as", because that constraint can be expressed by just re-using the same variable name.