# The Topic of Math



## Joasis (Mar 28, 2006)

I hired a new kid, and when we placed the rafters on the hangar project, and inserted the bolts, he asked me how I knew they would hold? :whistling 12 bolts, 1 inch diameter, grade 5. #5800 in shear. 

So I began explaining shear strength, and load design....and I could see he just didn't get it. 

We lifted the #3000 rafters with 4 load chains, and he was deathly afraid of being anywhere close... :no: I told him that the chains we use are rated for #4700 pounds, and since we are lifting with 2 chains, halving the load, it was all good. :thumbsup:

I swear, basic math seems to be a lost art...or what? 

Just a thought for a thread, how many of you guys explain the math we use and try to generate interest in why it is crucial to know.


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## Warren (Feb 19, 2005)

I think by the time your an adult, math can be hard to teach in the field. Most guys have already decided that they just don't get it or like it. I for one love math! I never took any math beyond the tenth grade, but I still love working with engineers, truss designers, and architects and discussing the specifics of loading, spans, shear, etc. Most carpenters nowadays simply rely on their calculators, or just let others figure the math for them.


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## Joasis (Mar 28, 2006)

When we built the underground home, the math I had to use on the shoring was complicated, and I loved the challenge. What was better yet, was the doubting looks from spectators.....they could not believe we were pouring concrete on Styrofoam forms with shoring posts every 4 feet on top of 4x4's.....didn't do me any good to explain the math....concrete @ #90 per sq/ft and 16 sq/ft supported by on shore....etc.


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## CrpntrFrk (Oct 25, 2008)

I wish I knew more math. I have never had anyone who knows the type of math you guys talk about on here teach me any of that. I have picked up on stuff on my own along the way but nothing like what you guys talk about.

I really like math though. Every time you guys have a numbers thread I read through it a couple time to try to pick up something new.


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## Kent Whitten (Mar 24, 2006)

Joasis said:


> I swear, basic math seems to be a lost art...or what?


It's basic anything Jay. There's quite a bit of lost art everywhere you look in today's youth. I coach baseball for kids around the 13-18 year age....it's shocking what some of these kids think. They will be in for a very rude awakening.


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## Warren (Feb 19, 2005)

Anything like that here would have to be stamped by an engineer. Most of my math is just working with simple spans, figuring rafter lengths, sq footage, material lists etc. These are pretty basic on the math spectrum, but I am surprise by the number of people who either cannot do the basics, or struggle with them.


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## Kent Whitten (Mar 24, 2006)

Few years back I posted a thread about this. We were hiring for the digital templating I was doing for the granite company. The equipment read in digital inches. I think it was thousandths of an inch. Anyway, I needed whoever we hired to be able to convert a digital inch to a fractional inch for paperwork. I gave a simple equation, convert 0.375" to a fraction. Not one could, not even the engineer that applied. One is pretty stuck when you can't find one person who can do what I consider basic conversion.


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## flashheatingand (May 3, 2008)

In the construction field, I think basic knowledge of math is necessary. Sometimes, I see myself moonlighting as a math teacher as well. As mentioned before, we aren't talking about the high levels, but basic math. It shocks me to see what our schools, no parents, are letting our kids get away with.

For those who aren't good at math, remember this simple expression, it will simplify many equations: Please Excuse My Dear Aunt Sally. (parrentisis, exponents, multiplication, division, addition, subtraction)


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## Cole82 (Nov 22, 2008)

I can do pretty much all the math I have run across on a calculator. But I was never taught how to do it long hand written out.

Cole


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## angus242 (Oct 20, 2007)

I have always been pretty terrible at math. Once I got into tile, it was a quick learning curve. Lots of geometry. I'm sure there are quicker methods of calculating but I eventually get to the right answer. :laughing:


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## CENTERLINE MV (Jan 9, 2011)

We have an old timer engineer that does all of his calculations scribbled on a piece of paper without ever using a calculator. Don't even think he knows what one is:laughing: It's really impressive watching him work.


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## Youngin' (Sep 16, 2012)

Basic math I can do. I wish I knew more about figuring angles though. For example, trying to run baseboard down a stair stringer against a wall. The stringer starts flat for 6 or so inches then begins it's descent with the risers. That's 2 separate pieces of baseboard there but what's the angle to cut it? 

I've only been in the trade for a couple years and I'll be the first to admit I'm young and dumb but there's gotta be a better way than test fitting angles till it works. I do ask different journeymen but I've never got a good answer that involves math.


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## JSM_CC (Jul 25, 2012)

Youngin' said:


> Basic math I can do. I wish I knew more about figuring angles though. For example, trying to run baseboard down a stair stringer against a wall. The stringer starts flat for 6 or so inches then begins it's descent with the risers. That's 2 separate pieces of baseboard there but what's the angle to cut it?
> 
> I've only been in the trade for a couple years and I'll be the first to admit I'm young and dumb but there's gotta be a better way than test fitting angles till it works. I do ask different journeymen but I've never got a good answer that involves math.


Study a protractor. Just remember you can add different angles to get to a right angle or a straight line. Also the intersecting line is the difference between the two angles. Course you can always scribe lines and then connect the dots where they intersect.


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## Inner10 (Mar 12, 2009)

Anyone who studied economics knows that you may as well be getting a degree in calculus. Since then I've never used it, I use basic calculator functions but nothing like what I did in school.


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## SC sawdaddy (Oct 15, 2008)

We;ve had an ongoing discussion this week about plumb and leve and common and hip rafter cuts. I think I explained it so that my helper understood it. At least he was able to identify the cuts on a speed square yesterday. I bet I have to explain it all again Monday though.


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## Jaws (Dec 20, 2010)

No one wants to understand why, just how. :no:

Guy who knows why and how, and can break projects down into manageable tasks, schedule accordingly, is going to be the boss. That works for me.:thumbsup:

When I was in the ditch and humping lumber, I was studying everything the nailer did. When I was the nailer, I was studying everything the cutman did, then the layout. Asked a million questions at lunch, read books, ect... so the first chance I could get a better job or position. :thumbsup: Should be the natural order of things. Problem is most just want the money and a tittle, not to be a true profesional in their feild. :no:

As far as math, always been good at it naturally, and I like it. Most of the math past Plane Geometry ( Trig and College Alegebra) is lost now, i have forgotten it. I dont need it, but wish I could remember it. Algebra 2 from junior year in high school and Geometry are what I use all the time, especially when I was still doing carpentry. The geometry you learn in trigonometry is not needed for what I do as a residential builder, or as a carpenter. Maybe engineering. Basic math is what i use the most now, usually for layout. 

The problem runs deep. Kids are taught what to think and not how to think, and that is going to make for a dumb nation, I am afraid. Critical thinking is more important than memorizing dates and facts as far as I am concerned. 

Another major issue is the lackadasical and whimsical attitude that when you are pretty good or pretty knowledgable (sometimes not even pretty good) that you are done learning and are a bad azz. I read about my profession and related topics like business and marketing, sales, ect... all of the time. The learning is never done, everything changes and evolves, it never stays the same. A lot of young guys who should be earning their spurs just want to go home and do whatever, not read. most dont even own a code book, or ask to borrow one. 2 years in the field and they are experts.:no::no:


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## Joasis (Mar 28, 2006)

It all boils down to what we teach our kids, or rely on the schools to teach.

When I taught aviation maintenance technology, it became clear that I could teach pretty complex math as long as I could show a need for it. Since then, I have always maintained that teaching in theory doesn't work for most kids.....

I know a lot of pilots that can handle the math in navigation, but have a hard time balancing their checkbooks.


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## J F (Dec 3, 2005)

For anyone really wanting to learn, there are_ lots_ of resources online. Do a search for math courses, you'll find tons of stuff.


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## Oconomowoc (Oct 13, 2011)

I just need to know addition


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## J F (Dec 3, 2005)

No multiplication?


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