MEASUREMENT & DIMENSIONS Plastic Technology

MEASUREMENT & DIMENSIONS Essential Question for the Lesson How do we use measurement?

READING A RULER The red lines on these rulers are marked at 1/2, and 1 The red marks on these rulers are at 1/4, 1/2, 3/4, and 1. (1/2 is the same as 2/4) The red marks on these rulers are at 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and 1. The red marks on this ruler are at 1/16, 1/8, 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, and 1.

DIVIDING FRACTIONS In building/designing there will be several times you will need to determine half of a specific measurement. When dividing fractions by 2, we will multiply the fraction by the reciprocal of 2 which is ½. Our numerator is multiplied by 1 and the denominator is multiplied by 2. Ex: What is half of 5/8? *Hint: Simply double the denominator. Answer=5/16

DIVIDING FRACTIONS ¾= 1/8= 5/16= 7/8= 1-11/16= Divide the following fractions in half: ¾= 1/8= 5/16= 7/8= 1-11/16= *Trick to divide mixed numbers: 1-11/16=? Numerator= 16x1+11=27 Denominator= 16x2=32 Answer=27/32 3/8 1/16 5/32 7/16 27/32

ADDING FRACTIONS Make sure the bottom numbers (the denominators) are the same (Least common denominator) Add the top numbers (the numerators). Put the answer over the same denominator as in step 1 Simplify the fraction Ex: What is ¼” +5/8”? *Hint: Find the least common denominator of each fraction. Answer=7/8” 8 is the LCD ¼=2/8 5/8=5/8

ADDING FRACTIONS ½ +1/4= 1/8+3/4= 5/16+1/4= 7/8+3/16+3/4= Add the following fractions: ½ +1/4= 1/8+3/4= 5/16+1/4= 7/8+3/16+3/4= 11/16+1/8+1/4= 3/4 7/8 9/16 29/16=1-13/16 17/16= 1-1/16

Converting Decimals ½ = .5 ¼ = .25 ¾ = .75 1/8 = .125 3/8 = .375 ¼ = .25 ¾ = .75 1/8 = .125 3/8 = .375 5/8 = .625 7/8 = .875

Converting Decimals 1/16 = .0625 3/16 = .1875 5/16 = .3125 7/16 = .4375 9/16 = .5625 11/16 = .6875 13/16 = .8125 15/16 = .9375

PRACTICE SHEET Complete the following practice sheet individually. Be sure to make your answers are recorded in feet and inches.