By the way, for example, the ratio of 3:4=6:8 is 3:4, and the front and rear items are increased by 2 times at the same time, which is in direct proportion. 3X4= 12, 2X6= 12, the former item becomes 2, and the latter item becomes 6, indicating that the former item decreases and the latter item increases, so it is inversely proportional; Fraction can be said to be the deformation of ratio, and the same is true.