Specify the sets in Problem by roster. a. (Distinct letters in the word Mathematics)
b. (Current U. S. president)

a. {m,a,t,h,e,i,c,s}

b. {Donald Trump}

Step-by-step explanation:

In tabular or roster form of the sets the elements of the sets are written in curly brackets and shown as sets. The elements of the set are separated by commas.

a. (Distinct letters in the word Mathematics)

{m,a,t,h,e,i,c,s}   (In this set the letters are not repeated as distinct letters were asked about)

b. (Current U.S. president)

{Donald Trump}  (since there is only one element so it does not need to be separated by a comma).

step-by-step explanation:

1. practice, practice & more practice

2. review errors

3. master the key concepts

do not try to memorise the processes.

4. understand your doubts.

5. create a distraction free study environment

6. create a mathematical dictionary

7. apply maths to real world problems.