IATSE 873 Carpentry Trade Test Tuneup



CARPENTRY Construction Math



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Use a calculator


Example 2); 5 9/16″ + 3 7/8″ - 7.2369″ + 9 11/12″ =

Change the fractions into decimals

9/16 to decimals = 9 ÷ 16 = .5625

7/8 to decimals = 7 ÷ 8 = .875

11/12 to decimals = 11 ÷12 =.9167

5.5625″+3.875″-7.2369″+9.9167″ 12.117″ = 12 1/16″

You will need to be able to convert feet and inches into decimals and back again.

14″ = 1.167′

14″ = 1′ -2″


Change 2 inches to decimals of a foot; 2 ÷ 12=0.167′

A quick calculation is; 14″ ÷ 12″ = 1.167′



From decimals to fractions using a calculator; 

Write your numbers down 

You have calculated an equation and the answer = 6.76438′

How do you change it to feet, inches and fractions?

6.76438′ ; 6 is the full feet number

.76438 is inches x 12 = 9.17256 - 9 is the full inches

.17256 is the inch fraction x 16 = 2.76096 round up to 3 or down to 2

Making the fraction 3/16″ Or 1/8″

6.76438′ = 6′-9 3/16″ Or 6′-9 1/8″

Now you can read it on your tape measure





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