please show how the process should be done in matlab, please show codes

Question 3 (25\%): Write a script that will: a) (10\%) Sum up n1 for n=1,2,,1000. Ex: 11+21+31+ b) (10\%) Repeat (a) but this time round the n1 to 2 decimal digits and then sum them up. c) (5\%) Calculate the absolute error between the true sum, from (a), and the rounded sum, from (b)