Xn=a[ 1-( 1+b)^n]/-b

Where X stands for the total amount of ***n years (including income and principal), A stands for the amount invested each year (for example, 200 yuan is invested every month, a = 2,400 yuan), B stands for income (for example, annual income 15%, b = 0. 15), and N stands for the power of n (Baidu can't mark it, so it has to be expressed.

For example, the annual income of a fund is 15%, and I want to buy 1 000 yuan per month for 20 years. After 20 years, what is the profit plus principal?

X20 =1000 *12 * [1-(1+0.15) 20]/-0.15 ?1.

Income = 1.23 million-20 *12 *1000 ≈ 990,000 yuan.

Note: The above rates are not included, because there are not many rates that are not considered. If the fund subscription fee charged by the front end is charged by a percentage every month, the redemption rate (back-end subscription redemption fee) is calculated according to the first-in-first-out principle.