Oh boy! Do i need help!
 

I was given a kit awhile back. So today I started cutting. I have a 13 3/4 X 41" piece fabric
The direction say to ..............
cut (4) 2 1/2 X 42" strips: crosscut into .....guess she means sub cut.
*(8) 2 1/2 X 10 1/2" rectangles
*(8) 2 1/2 X 6 1/2" rectangles.
To start off with I don't have 42" Is there anyway to cut this and get enough rectangles?

I think I understand what you are asking. Actually, from 13.75" you have enough for five 2 1/2 inch strips but you only need 4 - this is how I would cut it:

You can cut 3 - 10 1/2 inch pieces and 1 - 6 1/2 inch pieces on two of them (38" total)
Next one cut 2 - 10 1/2 inch pieces and 2 - 6 1/2 ' pieces (34" total)
Last one cut 6 - 6 1/2 inch pieces

looks like someone beat me to it.

Not sure about the directions but if you mean to crosscut/subcut those
(4) 2 1/2 x 42" strips into (8) 2 1/2 X 10 1/2" rectangles and
(8) 2 1/2 X 6 1/2" rectangles. Then, yes you will have enough.
First you cut (4) 2 1/2 x 41". Then you take each strip and cut
(2) 2 1/2" x 10 1/2" + (2) 2 1/2" x 6 1/2"
That will give you 8 strips of 10 1/2" and 8 strips of 6 1/2" long.
Hope this is clear.
You can draw in on square paper first. It's called a cutting plan.

So evidently all your pieces are 2 1/2" wide, right? 13-3/4" divided by 2.5" = 5.5. So you can get five 2-1/2" strips out of your piece. Multiply 5x41"=205. By my calculations, you only need 136 inches, so you should have plenty. I think I did this right ;-)

Thank you. There is only this one piece. I drew out your directions and it works with some left over. I really thought I was in deep doodoo. How did you figure it out? Is there a formula or do you just see it in your head?
This kit was won by a quilting friend and she is burned out of quilting and gave it to me. I am making it for her.
Thanks again.

I am glad someone else was able to help you. Lots of smart people on this board. Math was not my strong point.

Kings Daughter's calculation was where I started. But the rest - no formula - lol - just addition! I always start with the largest piece - fit in those first then fit in the smallest pieces.