Did I get this fraction subtraction problem right

haha fraction subtraction that rhymes.

Anyway. I keep doing this one problem for this test I've been resetting and I keep getting it wrong. It's a simple word problem that requires subtracting fractions.

Here is the problem: Xavier's dining room table was unstable because one leg was shorter than the others. He placed a 7/8 inch thick piece of wood under the short leg, and it became even with the other legs, which are 18 3/4 inches long. How many inches long was the short leg before Xavier added the wood?

My answer: 17 7/8
Please tell me I'm right!

Yes, you've got it right. Here's a quick and dirty: Subtract the fractions only: 3/4-7/8, find the common denominator which is 8 and you have 6/8-7/8... humm, not good enough because 6/8 is smaller than 7/8. Borrow 1 from 18 (now you have 17), and add it to 6/8: 8/1+6/8=14/8. Now we're cookin'!: 14/8-7/8=7/8, so we have 17 7/8 as your answer.
P.S. I did this in my head and then quickly wrote it, I hope you can follow my steps OK

18 3/4 - 7/8

3/4 = 6/8

18 6/8 - 7/8

(18 + 6/8) - 7/8

(17 + 1 + 6/8) - 7/8

(17 + 8/8 + 6/8) - 7/8
combine the fractions within the parentheses

(17 + 14/8) - 7/8

17 + (14/8 - 7/8)

17 + 7/8 = 17 7/8 <==== you are correct!

You're absolutely right...
18 3/4 - 7/8 = 75/4 - 7/8
= 17 7/8

Yes, you are right. [I would take 6/8 (of the 7/8) from the 18&3/4 getting down to 18 even; then I'd take the rest (1/8) from the even 18.]