Stuck on this MATLAB question

I'm supposed to write a code on MATLAB that solves this problem.

21855372, 21397898, 21303234, 21849704, 21647943, 21485234, 21825033

Take the last three digits of these numbers above and divide them by 1000. Then find arithmetic average of the numbers obtained.

[Steven Lord]

If you show us where you're stuck (which of the steps you don't know how to do) and describe what you've tried we may be able to offer some suggestions.

[Sara Maria El Oud]

I'm not really sure how to make it into a function that I can run to produce the output which is the arithmetic average. I used the command 'num2str' to extract the last 3 digits from the numbers, I've divided them all by 1000 and I tried to take the average however I think the way I'm supposed to do it is I'm supposed to turn it into a function that I can run. I'm kind of new to MATLAB and its frustrating because this is an easy question I just don't know how to solve it via this program. Help would be much appreciated!

[Star Strider]

Duplicate of: https://www.mathworks.com/matlabcentral/answers/353800-i-ve-been-stuck-on-this-matlab-question

Answer 1

[itend]

% input your values
x = 21855372
x1 = 21397898
x2 = 21303234
x3 = 21849704
x4 = 21647943
x5 = 21485234
x6 = 21825033

%take the last 3 digits
y = num2str(x) 
yout = str2num(y(6:8))

y1 = numstr(x1)
yout1 = str2num(y1(6:8))
etc. 

%divide each by 1000 and find mean
(y/1000 + y1/1000 + yn/1000...) / (7)

That should do it. Let me know if you have any other questions!

Answer 2

[Jan]

Start with

x = [21855372, 21397898, 21303234, 21849704, 21647943, 21485234, 21825033];

Taking the last 3 digits is the same as the remainder if you divide by 1000. The mod or rem command will help here. But if you divide these numbers by 1000 afterwards, both together is the same as the fractional part after the division by 1000.

Now creating the arithmetic mean is not hard. sum might help or what about using the mean command? Try it and ask a specific question in case of problems.