If you want to copy a formula from one cell to another (or fill down) without Excel changing the cell references automatically, you'll need to write the cell references with dollar signs included for absolute referencing.
Eg: the reference '$D3' locks the reference to column 'D' but allows the row to change when the cell is copied.
Eg: the reference 'D$3' locks the reference to row '3' but allows the column to change when the cell is copied.
Eg: the reference '$D$3' locks the reference to column 'D' and row '3', so the cell reference cannot change at all when the cell is copied.
While you are typing in a cell reference, pressing the 'F4' key will cycle through the combinations for you, so you don't need to type the dollar signs yourself.
Absolute Reference
An absolute cell reference will not change when it is copied.
No but if you replace a constant with a function it will remain a formula
They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.They are not always necessary. If your formula is not going to be copied then you don't need them. If you are copying a formula using a VLOOKUP function, then the reference to the cells for your table will change and then your formula won't work, because it won't be looking at the correct cells for your table. If you use the dollar signs then the reference to the table will not change when the formula is copied and the function will work correctly. The dollars change them to absolute references, so they stay the same when copied. Without the dollars they are relative references and will change when the formula is copied.
You use a mixed or an absolute reference. This is done by adding dollar symbols into a cell A1 is a relative reference and will change when copied. $A1 is a mixed reference, in which the row reference changes but the column reference does not. A$1 is a mixed reference, in which the column reference changes but the row reference does not. $A$1 is an absolute reference, so neither the column or row reference changes. In most cases only a mixed reference is needed, though it is common to use an absolute reference. You lock the column reference when copying a formula across a row and you lock the row reference when you are copying a formula down a column. It is only on the very rare occasion that a formula is being copied both down and across, into a block, that an absolute reference is needed.
A relative reference will change and a mixed reference will partially change. See the related question below.
To reference an Excel sheet in a formula or function, you can use the sheet name followed by an exclamation mark (!) before the cell reference. For example, to reference cell A1 in a sheet named "Sheet1", you would write "Sheet1!A1" in the formula.
No but if you replace a constant with a function it will remain a formula
It can be called a constant or fixed value. If it is not a value but a cell reference then it can be called an absolute reference.
B17 is a relative reference. $B$17 is an absolute reference. See the related question below.
The answer depends on what information you already have. The simplest version of a formula is f(x) = c.
In most cases where people use an absolute reference, a mixed reference will do. A mixed reference will lock a column or row, but not both. Most formulas are copied either down or across, but rarely both. If a cell needs to be locked in a formula, then we lock the row when copying down or lock the column when copying across. See the related question below for more details on the different kinds of cell references.