Add and subtract first, then multiply and divide. It is the same as the integer mixing operation. Different denominators should be divided, the denominator of the common denominator is the least common multiple, and then the denominator remains the same, and the numerator is added and subtracted. If it is multiplication, multiply the numerator by the numerator and the denominator by the denominator. In case of division, multiply the first fraction by the reciprocal of the second fraction. ...