How to find the mean, median and mode of mixed numbers giving the answers in lowest terms explain the way because i dont understand

To find mean you have to do number added together. so for example like you have the number like... 90, 75, 85, 65,80. then you add together 90 + 75 + 85 + 65 + 80 then you have to divided by the number how many you have so (90 75 85 65 and 80) so this example number has 5 of them then you
90+75+85+65+80/5
= 395/5
so the answer is 79.

MEDIAN : to find median you have to do write down lowest to highest.
ex.) 15,21,21,12,1,24,18
so I am going to find median for this numbers. index finger one of each number so like what I mean is left hand on number 15 on the left side and right index finger on right hand number 18, then you do your both index finger come down together at the same time so left index finger will be first number of 21 and right index finger will be 24, then you go down again left index finger will be second number 21 and then your right index finger will be on number 1 so then that means you have a 12 number alone right? you can find the answer like this or you can do another way you can write lowest to highest number to find median so far example what I mean is 1, 12, 15, 18, 21, 21, 24. like this. and your instructions are the same.

MODE : mode means that many numbers that you have so for numbers up there like 15, 21, 21, 12, 1, 24, 18 number your mode will be 21 because on this 7 number you have 21 is the many numbers that you have 2 of 21's.