Transcript USING LAYOUT TOOLS

USING LAYOUT TOOLS
8th Grade Shop Skills
System of Measurement
• English – standard measurement in the
United States, now called U.S. Customary
System
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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
System of Measurement
• Metric System – used for scientific work in
the United States
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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
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.
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
Reading a Ruler
• How many marks are there to an
inch on this ruler?
– 16
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.
Reading a Ruler
• Look at the lengths of the lines to determine measurement.
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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
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 /8th
• Fold in half again to get 1,3,5,7,9,11,13,15, 16ths
Reading A Ruler
• The Letter A represents what
measurement?
– 1”
Reading A Ruler
• The Letter B represents what
measurement?
– 1 7/16”
Reading A Ruler
• The Letter C represents what
measurement?
1 14/16” or 1 7/8”
Reading A Ruler
• The Letter D represents what
measurement?
2 11/16”
Reading A Ruler
• The Letter E represents what
measurement?
3 1/16”
Reading A Ruler
• The Letter F represents what
measurement?
3 5/16”
ONLINE PRACTICE
• http://www.rickyspears.com/rulergame/
• http://www.funbrain.com/measure/index.ht
ml
Working With Fractions
• What is a fraction?
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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
Working With Fractions Online
• http://www.visualfractions.com/EnterFracti
on.html
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
Adding Common Denominators
• 1/4+1/4=
• 1/8+5/8=
• 2/4
• 6/8
• 3/4+3/4=
• 3 / 16 + 3 / 16 =
• 6/4
• 6 / 16
• 1/8+3/8=
• 4/8
• 5/8+7/8=
• 12 / 8
• 1 / 16 + 5 / 16 =
• 6 / 16
• 7 / 16 + 5 / 16 =
• 12 / 16
Adding Fractions Online
• Add Fractions With Like Denominators
using Circles
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
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
Adding Uncommon
Denominators
• http://www.visualfractions.com/AddUnlike
Circle.html
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)
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
Reducing Fractions
• http://www.visualfractions.com/LowestCirc
le.html
• http://www.learningplanet.com/sam/ff/inde
x.asp
Adding Compound
• 1st Method
– Convert the whole numbers to fractions and add
like or common denominators
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1 3/8+2 5/8=
11 / 8 + 21 / 8 =
32 / 8 =
4
Adding Compound Fractions
• 2st Method
– Add the fractions together then add the whole
numbers to the fraction
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1 3/8+2 5/8=
3/8+5/8=
8/8=
1
1+1+2=4
Adding Compound Fractions
• http://www.visualfractions.com/AddStrictCi
rcle.html
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
Subtracting Common
Denominators
• 1/4-1/4=
• 5/8-1/8=
• 0/4
• 4/8
• 3/4-3/4=
• 3 / 16 - 3 / 16 =
• 0/4
• 0/ 16
• 3/8-1/8=
• 2/8
• 7/8-5/8=
• 2/8
• 5 / 16 -1 / 16 =
• 4/ 16
• 7 / 16 - 5 / 16 =
• 2 / 16
Subtracting Fractions Online
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
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
Subtracting Uncommon
Denominators
Subtracting Compound Fractions
• 1st Method
– Convert the whole numbers to fractions and
subtract like or common denominators
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2 5/8 -1 3/8=
21 / 8 - 11 / 8 =
10 / 8 =
1 2/8
1 1/4
Subtracting Compound Fractions
• 2st Method
– Subtract the fractions then subtract the whole
numbers then add results together
–2 5/8 -1 3/8=
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5/8-3/8=
2/8
2–1=1
1 + 2 / 8 = 1 2 / 8 or 1 1/4