The yellow ribbon is 53 meters long, shorter than the red ribbon 18 meters, and the red ribbon is 7 1 meter long. According to relevant public information, the yellow ribbon is 53 meters long, which is shorter than the red ribbon by 18 meters, and the length of the red ribbon is equal to 53 plus 18 and 7 1 meter. Mathematics is a subject that studies concepts such as quantity, structure, change, space and information.