When I was in elementary school learning math, I was told,
like so many other students, that no matter what you do, you will need
math. How right they were. I use math every day at the quilt shop and
not just to figure up the cost when I ring up a sale. I am often asked to figure up the yardage
needed for a quilt or how many five inch squares can be cut from a half
yard. Not to mention that I have to
convert inches to fractions to decimals just to get the yardage from a pattern
to the checkout stand on nearly a daily basis.
I will forever be grateful that I knew how to find the circumference of
a circle when a customer asked how much rick-rack she needed to go around a
circle 40 inches in diameter. Geometry,
fractions, measurements, even algebra I use on a fairly regular basis.
Yet the problems that I deal with are not anything like the
simple, straight forward word problems that we were given in elementary
school. There should have been a whole
section in school just for quilting math.
Even simple addition is different in quilting. Normally an addition problem would look like
this: 2 + 2 = 4. Simple. Yet if you were to sew a two inch strip of
fabric with another two inch strip of fabric, you would normally get a 3 ½”. Somehow, with quilting, even the most fundamental
rules don’t seem to apply. Really the
equation looks more like this, (2 - 1/4) + (2 - 1/4) = 3 1/2 because you need
to account for seam allowance. Probably
the most common question I am asked is to figure the yardage for a
backing. In school, figuring the area of
a rectangle was pretty straight forward.
L x W = Y
Length times width equals area. Figuring a backing, however, is a little more
difficult. You also have to take into
account the width of the fabric. The
real formula looks more like this:
(L/42)(W+6)=Y
36
Of course, even this doesn’t take in to account that L/42
must be rounded up before multiplying it to W+6 or that L and W could be
switched if that would use less fabric and be more affordable to the customer.
For those of you who think you could hack it as a quilt
mathematician, here is a story problem, one that I actually had to solve at the
shop one day:
Suzy would like to make a quilt using the
disappearing nine patch pattern. How
many layer cakes would she need to buy to make a queen sized quilt without
borders?
Now, for those of you who are not quilters, you may think
that I haven’t given you enough information: And you are right, there are no
numbers in this story problem (unless you count that nine which is really part
of the title and really doesn’t help much).
How can you solve a math problem with no numbers? Most quilters will recognize the hidden or
implied numbers. So, in fairness to any
non-quilting readers, here are a few hints to help you out.
- A layer cake is a set of pre-cut, 10 inch
squares and there are usually 40-42 squares in a pack.
- A disappearing nine patch is made by sewing squares
together in sets of nine, 3 down and 3 across, and then cutting these assemblies
in half twice, first up and down and then across, making four blocks which are
then rearranged and sewn together to form the quilt
- A queen sized quilt measures about 84” x 92”.
- Don’t forget to account for ¼” seam allowance.
These problems won’t get you an A+ or a gold star. There is no prize for excellence in the area
of quilt math or a trophy for the first person across the finish line with the
right answer. Yet there is something
rewarding about solving these convoluted problems. It is something akin to solving a Sudoku
puzzle or answering trivia questions on a game show. It’s good to challenge your knowledge and
reasoning abilities sometimes, to test yourself and stretch your brain and really
think. This and the ability to help
those that come into the shop is really all the reward I need. To those of you who wish to take the challenge,
good luck, have fun, and make sure you show your work!