Emma's marble = m
So, Dave has = m + 10
So, your final answer is m + 10
Hope this helps!
Lets divide the problem in parts, first for sandwiches she used 3/4 out of 20 ounces of ham:
(3/4)(20) = 60/4 = 15
so for sandwiches Lauren used 15 ounces
Then for omelete she used 1/5, that is:
(1/5)(20) = 20/5 = 4
then Lauren used 4 ounces for omelete
So Lauren used 15 ounces for sandwiches and 4 ounces for omelete, that is 19 ounces in total, so there are left from the 20 original ounces:
20 - 19 = 1
there is 1 ounce of ham left
The absolute value of a number is the distance away from zero that number is. The absolute value "gets rid" of the negative sign

15 is the answer