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USING LAYOUT TOOLS 8 th Grade Shop Skills
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System of Measurement English – standard measurement in the United States, now called U.S. Customary System –Uses, inch, foot, yard, rod and mile as units –12 inches in a foot –3 feet in a yard –16 ½ feet in a rod –5,280 foot in a mile
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System of Measurement Metric System – used for scientific work in the United States –Measurements are based on the meter –1 Meter = 100 centimeters (cm) –1 Meter = 1,000 millimeters (mm) –1000 Meters = a Kilometer (km) Units are in multiples of 10
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Inch as a Unit of Measurement Traditional unit for woodworking and metalworking Some fine rules or scales have 32 marks per inch. Most rules have 16 marks per inch with each mark equaling 1/16 of an inch.
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How To Read a Ruler Identify how many marks there are to an inch. Measure item and count how many marks past a whole number. Reduce to least common denominator
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Reading a Ruler How many marks are there to an inch on this ruler? –16
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Reading a Ruler Locate the marks for 1”, 2”, 3” and 4” Inch marks are the longest, usually the number is located under or to one side of the line.
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Reading a Ruler Look at the lengths of the lines to determine measurement. –The longest line is for a whole number 1 –Next longest line is for 1 /2 –Next longest line is for 1 / 4 and 3 / 4 –Next longest line is for 1 / 8, 3 / 8, 5 / 8 and 7 / 8 –Remaining lines are 1/16, 3/16, 5/16, 7/16, 9/19, 11/16, 13/16, 15/16
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Make Your Own Ruler On the strip of paper given to you, write 0 on one end and 1 on the other. Fold in half and draw line on the crease, write 1 / 2 at the crease. Fold in half again. The creases created are 1 / 4 and 3 /4 Fold in half again to get 1, 3, 5, 7 /8 th Fold in half again to get 1,3,5,7,9,11,13,15, 16ths
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Reading A Ruler The Letter A represents what measurement? –1”
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Reading A Ruler The Letter B represents what measurement? –1 7/16”
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Reading A Ruler The Letter C represents what measurement? 1 14/16” or 1 7/8”
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Reading A Ruler The Letter D represents what measurement? 2 11/16”
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Reading A Ruler The Letter E represents what measurement? 3 1/16”
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Reading A Ruler The Letter F represents what measurement? 3 5/16”
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ONLINE PRACTICE http://www.rickyspears.com/rulergame/ http://www.funbrain.com/measure/index.ht mlhttp://www.funbrain.com/measure/index.ht ml
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Working With Fractions What is a fraction? –It is a portion of a whole –They have a numerator (Top Number) –And a denominator (Bottom Number) –1 / 2 would mean 1 part of 2
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Working With Fractions Online http://www.visualfractions.com/EnterFracti on.htmlhttp://www.visualfractions.com/EnterFracti on.html
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Adding Fractions With common (same) denominators –Add nominator –Denominators stay the same ¼ + ¾ = 4/4 3/8 + 5/8 = 8/8 3/16 + 7/16 = 10/16
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Adding Common Denominators 1 / 4 + 1 / 4 = 2 / 4 3 / 4 + 3 / 4 = 6 / 4 1 / 8 + 3 / 8 = 4 / 8 5 / 8 + 7 / 8 = 12 / 8 1 / 8 + 5 / 8 = 6 / 8 3 / 16 + 3 / 16 = 6 / 16 1 / 16 + 5 / 16 = 6 / 16 7 / 16 + 5 / 16 = 12 / 16
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Adding Fractions Online Add Fractions With Like Denominators using CirclesAdd Fractions With Like Denominators using Circles
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Adding Fractions With uncommon (different) denominators –One or both fractions will need to changed so both will have a common denominator 3/8 + 3/16 –First change 3/8 to 6/16 by multiplying both the numerator and denominator by 2 6/16 + 3/16 = 9/16
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Adding Uncommon Denominators 1 / 2 + 1 / 4 = 3 / 4 1 / 2 + 1 / 8 = 5 / 8 1 / 2 + 1 / 16 = 9 / 16 1 / 4 + 1 / 8 = 3 / 8 1 / 4 + 1 / 16 = 5 / 16 1 / 8 + 1 / 16 = 3 / 16 3 / 16 + 1 / 2 = 11 / 16 5 / 16 + 3 / 8 = 11 / 16
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Adding Uncommon Denominators http://www.visualfractions.com/AddUnlike Circle.htmlhttp://www.visualfractions.com/AddUnlike Circle.html
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Reducing Fractions Reduce fractions to their least common denominator. Divide the numerator and denominator by the same number so both are whole numbers. 4 / 8 = 1 / 2 (both 4 & 8 can be divide by 2) 5 / 8 = 5 / 8 (cannot be divide and remain a whole number)
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Reducing Fractions 2 / 16 = 1 / 8 4 / 16 = 2 / 8 = 1 / 4 6 / 16 = 3 / 8 8 / 16 = 4 / 8 = 1 / 2 10 / 16 = 5 / 8 12 / 16 = 6 / 8 = 3 / 4 14 / 16 = 7 / 8 16 / 16 = 1
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Reducing Fractions http://www.visualfractions.com/LowestCirc le.htmlhttp://www.visualfractions.com/LowestCirc le.html http://www.learningplanet.com/sam/ff/inde x.asphttp://www.learningplanet.com/sam/ff/inde x.asp
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Adding Compound 1 st Method –Convert the whole numbers to fractions and add like or common denominators 1 3 / 8 + 2 5 / 8 = 11 / 8 + 21 / 8 = 32 / 8 = 4
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Adding Compound Fractions 2 st Method –Add the fractions together then add the whole numbers to the fraction 1 3 / 8 + 2 5 / 8 = 3 / 8 + 5 / 8 = 8 / 8 = 1 1 + 1 + 2 = 4
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Adding Compound Fractions http://www.visualfractions.com/AddStrictCi rcle.htmlhttp://www.visualfractions.com/AddStrictCi rcle.html
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Subtracting Fractions With common (same) denominators –Subtract nominator –Denominators stay the same 3/4 - 1/4 = 2/4 5/8 - 3/8 = 2/8 7/16 - 3/16 = 4/16
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Subtracting Common Denominators 1 / 4 - 1 / 4 = 0 / 4 3 / 4 - 3 / 4 = 0 / 4 3 / 8 - 1 / 8 = 2 / 8 7 / 8 - 5 / 8 = 2 / 8 5 / 8 - 1 / 8 = 4 / 8 3 / 16 - 3 / 16 = 0/ 16 5 / 16 -1 / 16 = 4/ 16 7 / 16 - 5 / 16 = 2 / 16
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Subtracting Fractions Online
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Subtracting Fractions With uncommon (different) denominators –One or both fractions will need to changed so both will have a common denominator 3/8 - 3/16 –First change 3/8 to 6/16 by multiplying both the numerator and denominator by 2 6/16 - 3/16 = 3/16
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Subtracting Uncommon Denominators 1 / 2 - 1 / 4 = 1 / 4 1 / 2 - 1 / 8 = 3 / 8 1 / 2 - 1 / 16 = 7 / 16 1 / 4 - 1 / 8 = 1 / 8 1 / 4 - 1 / 16 = 3 / 16 1 / 8 - 1 / 16 = 1 / 16 1 / 2 - 3 / 16 = 5 / 16 3 / 8 - 5 / 16 = 1/ 16
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Subtracting Uncommon Denominators
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Subtracting Compound Fractions 1 st Method –Convert the whole numbers to fractions and subtract like or common denominators 2 5 / 8 - 1 3 / 8 = 21 / 8 - 11 / 8 = 10 / 8 = 1 2/8 1 1/4
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Subtracting Compound Fractions 2 st Method –Subtract the fractions then subtract the whole numbers then add results together –2 5 / 8 - 1 3 / 8 = 5 / 8 - 3 / 8 = 2 / 8 2 – 1 = 1 1 + 2 / 8 = 1 2 / 8 or 1 1/4
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