Please see picture attached.
Answer:
Keisha has 1/8th of the sandwich that she brings back.
Step-by-step explanation:
To start, take a whole sandwich and subtract the 1/2 she left at home and the 3/8 that her family ate.
1 - 1/2 - 3/8 = Leftover
We also need to give them common denominators to complete the action.
8/8 - 4/8 - 3/8 = Leftover
1/8 = Leftover
First, she distributed

Which gave her

Then, she combined like terms

Which gave her

Then, she subtracted

from both sided
Which gave her

Then, she added

to both sides
Which gave her

And finally sh edivided 32 by 2 and got

hope this helps if you have any questions please pm me :)