Claire wants to place a mirror that is 18 and one half inches wide in the center of a wall that is 31 inches wide how far from each corner should she place the mirror for it to be ceentered

Claire should place the mirror 6 and 1/4 (6.25) inches from each corner of the wall in order for the mirror to be centered.  

Step-by-step explanation:

In order to find out how far the mirror would need to be set from each corner of the wall, you need to first take the total length of the wall and subtract the total width of the mirror:  31 - 18.5 = 12.5.  12.5 inches is the amount of wall space that would be left when the mirror is hanging.  In order for the mirror to be centered, we need to take the amount of wall space left and divide by two (2) to find the measurement from each corner:  12.5 ÷ 2 = 6.25 or 6 1/4.  By placing the mirror 6.25 inches from each corner of the wall, the mirror will be centered on the wall.