Measure from the center of one of your child's eyes to the center of the other eye with the ruler. Use this measurement to make 2 dots with the pencil in the center of the craft foam the same distance apart as your child's eyes.
Draw a 3 1/2-inch shape around each dot for the frames of the glasses. Draw a 1 1/2-inch circle inside each shape for the eye holes. Draw a 1/2-inch-wide strip connecting the 2 shapes. Cut out the frames of the glasses along the lines.
Punch holes on either side of the frames with the hole punch. Twist a pipe cleaner onto each hole to create earpieces for the shades.
Spread glue on the front of frames and decorate with the cereal. Let stand until dry.