Pusattinta.com Store is engaged in selling printer ink. The problem faced is difficult to determine the amount of stock to meet customer needs and not cause accumulation of goods for a long time. With the above problems, a forecasting application was made using the Java programming language with the WMA, SMA, and DES methods. The WMA method is assigned a different weight for each available past historical data, SMA is a value smoothing forecasting method by taking a group of observed values ??and looking for the average, DES processes smoothing twice. Where each data is given a weight symbol. The magnitude of is 0 to 1. From the 3 methods, it is known that the average MSE of each method is WMA : 102,898.57, SMA : 89,579,446 and DES : 87,156,989. The method with the smallest MSE average is the most appropriate method to use.

At this time the learning process is still partially carried out online (in the network) considering the positive cases of Covid-19 that still exist in the Semarang City area. The implementation of online learning is not without problems, even in several countries, especially Indonesia, it is reported that countries that adopt online learning on average are actually much smaller than expected. The implementation of online learning makes students less understanding of the learning materials provided and students' low interest in learning during the pandemic. This study aims to create a learning application for grade VI elementary school students that contains learning materials, practice questions that are randomized using LCM and facilitate the results of the assessment of the questions. From the results of LCM randomization, each student did not get the same or twin questions. From the test of 3 students, it was found that the questions that appeared in the same order were question number 6, while the questions that appeared in a different order were questions number 2, 3, 4, 5, 7, 8, 9, 10