Mathematically, it refers to the difference between (horizontal or vertical) coordinates of all intersections of a function and a coordinate axis, which can be any number. The intersection of the curve with the X and Y axes (a, 0) and (0, b), where A is the intercept of the curve on the X axis; B is the intercept of the curve on the y axis. Intercept and distance are different, and the values of intercept are positive, negative and zero. The value of distance is non-negative. Intercept is a real number, not a "distance", which can be positive or negative. The sum of intercepts is the sum of x-axis and y-axis intercepts. When solving a problem, if the intercepts of a straight line to the X axis and the Y axis are the same, we should consider the situation that the straight line passes through the origin. The intercept in a linear function is a linear function y=kx+b, then b is the intercept on the y axis, and k is the transverse intercept and longitudinal intercept of the slope: the straight line L intersects with the x axis at point A(a, 0) and with the y axis at point B(0, b), then A is called a straight line L.