USING LAYOUT TOOLS

8th Grade Shop Skills

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

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

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.– 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.html

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

Working With Fractions Online

• http://www.visualfractions.com/EnterFraction.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 =• 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

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/AddUnlikeCircle.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/LowestCircle.html

• http://www.learningplanet.com/sam/ff/index.asp

Adding Compound

• 1st 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

Adding Compound Fractions

• 2st 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

Adding Compound Fractions

• http://www.visualfractions.com/AddStrictCircle.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 =• 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

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• 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 =

• 5 / 8 - 3 / 8 =

• 2 / 8

• 2 – 1 = 1

• 1 + 2 / 8 = 1 2 / 8 or 1 1/4