Percentage is a basic and important concept in crypto.
It is a way of dividing something into 100 equal parts and then describe parts of it. i.e. If I have $1k dollars. And I spend $200 dollars from it, then what percentage of $1k I spent?
Formula = Parts/Total x 100
Calculation: 200/1000 x 100 = 20%
I spent 20% of $1k.
Now to find 20% of $1k is how much?
Formula = Total x (Percent in Fraction)
Calculation: 1000 x .20 = 200
20% of 1k is 200.
To represent percent in fraction, divide the percent by 100. i.e. 20% = 20/100 = 0.20 or simply 0.01 represent 1%, 0.02 represents 2%, 0.10 represent 10% and so on.
In crypto we usually see percent (APY, APR, ROI) while stacking/lending/borrowing etc. Equipped with the basics of percentage in the above para, now lets move on to find and understand these.
While stacking there is this APY%, it stands for Annual Percentage Yield, which means as to how much profit you would get yearly on an investment while stacking (saving). Now let suppose we have $1k USDT and we are stacking it and the APY% provided by the platform is 30%.
Calculation: 1000 x 0.30 = 300
It means we will get $300 per year while stacking $1k. Since there are 365 days in a year 300/365 = 0.82 per day. We will get 82 cents per day.
Note: 0.30 is equal to 30% while 0.03 is equal to 3%
APY, APR and ROI is a little bit different but you get the idea. Now you can use these basic maths skills to calculate APY% etc. and back & forth.