This molecule has no stereocenters (usually identified as a carbon atom attached to four different substituents. Therefore, the molecule is described as achiral.

In the molecule shown, carbon  is the only stereocenter. The hydroxyl group is first priority, the aldehyde group (on top of the molecule) is second priority, the rest of the molecule (the group) is third priority, and the hydrogen is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a clockwise directionality, so the absolute configuration is R.

This molecule contains two stereocenters, at carbon number  (containing the hydroxyl group), and carbon number  (containing the methyl group). 

For carbon , the hydroxyl group is first priority, the alkane group going across the top of the molecule is second priority, the alkane group going down the left side of the molecule is third priority, and the hydrogen (not drawn) is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a counterclockwise directionality, so the absolute configuration is S.

For carbon  , the alkane group moving across the top of the molecule toward the hydroxyl group is first priority, the alkane group going down the right side of the molecule is second priority, the methyl group is third priority, and the hydrogen (not drawn) is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a counterclockwise directionality, so the absolute configuration is S.

In the molecule shown, carbon number  (numbering with the alkene terminal carbon as number ), is the only stereocenter. The alkene group is first priority, the ethyl group is second priority, the methyl group is third priority, and the hydrogen (not drawn) is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a counterclockwise directionality, so the absolute configuration is S.

In the molecule shown, carbon  is the only stereocenter. The fluorine group is first priority, the alkyl branch containing the amino group is second priority, the methyl group is third priority, and the hydrogen (not drawn) is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a clockwise directionality, so the absolute configuration is R.

For the top chiral carbon (carbon number ), The hydroxyl group is first priority, the cyanide group is second priority, the branch forming the rest of the backbone is third priority, and the hydrogen is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a clockwise directionality, so the absolute configuration is R.

For the bottom chiral carbon (carbon number ), the hydroxyl group is first priority, the branch forming the top of the backbone is second priority, the  group is third priority, and the hydrogen is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a counterclockwise directionality, so the absolute configuration is S.

This molecule has two stereocenters. Numbering from left to right they are carbon numbers  and .

For the chiral carbon on the left (carbon number ) The bromine group is first priority, the rest of the molecule on the right is second priority, the methyl group on the left is third priority, and the hydrogen (not drawn) is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a clockwise directionality, so the absolute configuration is R.

For the chiral carbon on the left (carbon number ) The bromine group is first priority, the rest of the molecule on the left is second priority, the methyl group on the right is third priority, and the hydrogen (not drawn) is the fourth (lowest) priority. Placing the fourth priority away from the viewer, into the plane of the page/screen (on a dash), the order of the substituents from highest to lowest priority is , which follows a counterclockwise directionality, so the absolute configuration is S.

Aside from the hydrogen that extends "back into the page", priority 1 goes to the top right group (from the perspective of the TAS) because of the large chlorine atom. Priority 2 goes to the top left group because of the carbon atom attached to another carbon atom. Priority 3 goes to the methyl group because it is a carbon atom attached to hydrogen atoms, which have the lowest priority. When the hydrogen atom attached to the TAS is viewed as going back into the page, the circle created by going from priority 1 to priority 3 is counterclockwise, so we assign this TAS to be S. Cis and trans are irrelevant to TAS. 

Aside from the hydrogen that extends "forward from the page", priority 1 goes to the top left group (from the perspective of the TAS) because of the chlorine atom. Priority 2 goes to the bottom left group because of the carbon atom attached to another two carbon atoms. Priority 3 goes to the bottom right group, which has a carbon attached to only one other carbon at the point of difference with the group that has priority 2. When the hydrogen atom attached to the TAS is viewed as going back into the page, the circle created by going from priority 1 to priority 3 is clockwise, so we assign this TAS to be R. Cis and trans are irrelevant to TAS. 

The given images are Fisher projections of the molecules. To compare them, we must mentally rotate the substituents around the carbon-carbon bond through the molecule's center, as well as consider flipping the projection end-over-end.

If the molecule to the left were flipped directly end-over-end, it will match the molecule to the right, with the methyl pointed upward in the front plane and the ethyl pointed downward in the rear plane. These molecules are identical.