Begin by pairing two 5" charm squares right sides together. Draw a diagonal line across the lightest one.
Sew 1/4" from the drawn diagonal line on each side of the drawn line. Then cut apart on the drawn line.
Press the seam allowance to the dark fabric on each half square triangle.
Square the half square triangle to 4 1/2" by lining up the diagonal line on the ruler with the pressed line and trim off the excess
You will have 2 half square triangle units.
They are really no different whether you make them from a 5" charm square or you make them from any other size square. The technique is the same. The end result in this case is a 4 1/2" half square triangle that will pair up easily with the 4 1/2" 4-patch units you learned about last week. What block will you make with them.