Abstract: A method of summarizing a text by the following steps. Identifying the textual units in the text. Selecting a first set of textual units and identifying its textual units. Selecting a second set of textual units and identifying its textual units. Determining how many textual units are shared between the first and second sets of textual units. Selecting a third set of textual units between the first and second set of textual units and identifying its unique textual units. Determining the frequency of occurrence of the textual unit in the third set of textual units. Determining the frequency of occurrence of the textual unit in the text. Determining the proximity of the results of the last two steps. Calculating a score for the first set of textual units. Assigning the highest score to the first set of textual units. Selecting a numbers of first sets of textual units, according to score, as the summary of the text.

Abstract: A system uses objects that can be combined to learn mathematical operations. Operand objects illustrate a numerical operand and an associated set of possible numerical solutions to operations performed on the operand number. Operator objects illustrate an operation symbol and a numerical operator. When an operator object and an operand object are combined, a mathematical operation consisting of the operand, the operation symbol and the operator is illustrated, and a solution to the operation is illustrated. The operand objects also include a non-numerical representation of the value of the operand, and the operator objects also include a non-numerical representation of the value of the operator. When combined, the representation of the value of the operator, and the representation of the value of the operand cooperate to represent the value of the solution to the mathematical operation.