text: When you copy cells with formulas in them, Excel changes the the formula to make a guess as to what your new formula references should be.  However there are cases in which you do not what Excel to change a cell reference.  By putting the $ in front of the column or row reference Excel will not change it when copying.\n\nFor Example: A1 contains 10.  B1 through B10 contains a series of the values 1 to 10. In C1 you create the formula =A1*B1.  Now you want to copy this formula down 9 more times to multiply 10 times each number but when you do the copy, Excel automatically changes the formulas and such: A2*B2, A3*B3, etc.  So to keep A1 in the formula all the way down.  Make your formula =A$1*B1 (F4 key toggles this).  Then when you copy the cells the reference to A1 doesn't change for all formulas