Graph theory isn’t enough. The mathematical language for talking about connections, which usually depends on networks — vertices (dots) and edges (lines connecting them) — has been an invaluable way ...

To calculate the Consumer Price Index between two years in Excel, take a sum of all the amounts spent on the basket of products over those two years. Then use the following formula to find the CPI ...

If you understand the definition of a mathematical function, a good way to judge it is that any line drawn parallel to the y-axis intersects with the values in the function’s curve only once. The same ...