The first type of math worksheet contains a collection of similar math problems or exercises. A worksheet is simply a subset of the spreadsheet divided for the sake of clarity. Spread components handle spreadsheet data at the cell, row, column, or worksheet level. Unlike popular spreadsheets like Excel, Origin's worksheet is column oriented. Having a worksheet template easily accessible can help with furthering learning at home. A step-by-step worksheet for this calculation can be found in IRS Publication 560. All Kumon programs are pencil and worksheet based. See the Mathcad worksheet illustration of this straightforward application of the formula. An array of cells is called a "sheet" or "worksheet". Passwords can also be used to restrict modification of the entire document, worksheet or presentation. Each worksheet window is persistently bound to a file. Functions themselves cannot write into the worksheet, but simply return their evaluation. Often, the format is a structured interview during which a standard worksheet is completed. The National Fire Protection Association provides a risk assessment worksheet in their lightning protection standard. Software is increasingly taking over the paper-based worksheet.