Adding positive integers involves combining two or more whole numbers to find their sum. It requires identifying the integers to be added, expressing them numerically without fractions or decimals, then carefully adding each digit and carrying over when necessary to determine the total. Examples shown add positive integers like 5 + 7 = 12, 8 + 12 = 20, and 25 + 17 = 42 by simply combining the numbers. The main objective is to accurately calculate the total value.