Tuesday July 20, 2011Hubbs Center - Math 2Agenda and Objectives
Today’s Objectives... We will complete a real world math problem to show what we know about fractions. We will take notes on what we have learned to do with fractions. We will practice how to borrow when subtracting with fractions. We will practice word problems that require the addition and subtraction of fractions.
Real World Math Problem Joannabought 1 2/9 of a pound of chocolates and ate 1/6 of a pound. How much was left? Anton bought a board that was 3 4/5 yards long. He cut off 1/2 of a yard. How much was left?
Fractions Notes Rules for Adding Fractions: 1. Make sure the denominators are the same 2. Add the numerators. Put the answer over the same denominator. 3. Simplify (reduce) the fraction, if possible.– Example: 12/13 + 1/2
Fractions Notes Rules for Subtracting Fractions: 1.Change mixed numbers to improper fractions. 2.Make sure the denominators are the same. 3. Subtract the numerators. Put the answer over the same denominator. 4. Simplify (reduce) the fraction, if possible. Example: 5/8 - 1/10
Fractions Notes How to change an improper fraction into a mixed number: How to change a mixed number into an improper fraction:
Fractions Notes How to find a common denominator so you can add or subtract: Example: 3/7 + 5/81. List the multiples for both denominators (multiply the number x1, x2, x3...)2. Find the smallest multiple they have in common (the same).3. Multiply each fraction, top and bottom, to get that multiple.4. Add or subtract the numerators. Remember: What you do to the bottom of the fraction, You have to do the same to the top!
How to reduce or simplify fractions To simplify a fraction, divide the top and bottom by the highest number that can divide into both numbers exactly. Example: 24/108from: http://www.mathsisfun.com/simplifying-fractions.html
How to borrow when you subtract fractions First, think about how you solve: 25 -17 Next, think about how you might solve: 3 1/3 - 1 2/3
Addition and Subtraction Word Problems HW Sample Problems: