2+2=3 1/2

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.

1. A layer cake is a set of pre-cut, 10 inch squares and there are usually 40-42 squares in a pack.
2. 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 
3.  A queen sized quilt measures about 84” x 92”.
4. 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!