If love is 1, not love is 0. Both people love each other: 1×1=1 means they are in love; neither person loves each other: 0×0=0 means they do not love each other. There is one person who loves and one person who does not love: 1×0=0 One-sided love will not have any results. Both of them only love half of each other: 0.5×0.5=0.25. The content of love becomes less than half of the original. The world is so big, it is so easy to fall in love with someone, and it is so easy to be loved. But it is so difficult to love each other and stay together!