Can anyone me with these 2 questions

Sally will have 3 2/4
 and the second question is 81.1

1)
 4 5/8-1 3/4 = 23/8
 u can write 2 7/8

2)81.139
 if u round any number to any place first find that place like tenth place .
then find the next number after this place .
here it is 3 after tenth place.
if a number in range 1-4 they dont need to round but if a number is 5-10 range ,round your number Up
answer is 81.1

1.17+3.99a. you combine the terms with a to create 3.99 and the 1.17 stays because it has no like terms or a variable