Bellringer Do problems 1 – 6 on your study guide Be prepared to share your answers

Bell-Ringer: Find the least common multiple 1) 4 and 12 2) 8 and 3

Bell-Ringer: Find the least common multiple 1) 4 and 12 12 2) 8 and 3 24 3) 12 and 11 132 4) 4 and 7 28 5) 8 and 10 40 6) 15 and 40 120

Adding and Subtracting Fractions

Activity: FIND SOMEONE WHO

I will use the least common multiple to add and subtract fractions. Learning Objective: I will use the least common multiple to add and subtract fractions.

Adding Fractions with common denominators

Steps for Common denominators adding and subtracting fractions 1. Add/subtract numerator ONLY and bring denominator straight over. 2.Simplify

Lets Practice

Adding Fractions with different denominators Problem: You can’t add fractions with different denominators without getting them ready first. They will be ready to add when they have common denominators Solution: Turn fractions into equivalent fractions with a common denominator that is find the Lowest Common Multiple (LCM) of the two denominators

Steps for Common denominators adding and subtracting fractions 1. Find the LCM of both denominators to find a common denominator. 2. Multiply the numerator and the denominator by the same number to make the denominator the LCM 3. Add/subtract numerator ONLY and bring denominator straight over. 4.Simplify

Finding the Lowest Common Denominator The least common multiple of two numbers is the lowest number in BOTH lists of multiples Multiples of 2 are 2, 4, 6, 8, 10…… Multiples of 3 are 3, 6, 9, 12, ……… What is the lowest common multiple?

Finding the Lowest Common Denominator The lowest common multiple of two numbers is the lowest number they will BOTH divide into 2 divides into 2, 4, 6, 8….. 3 divides into 3, 6, 9…. What is the lowest number 2 and 3 both divide into?

You can’t add fractions with different denominators + The Lowest Common Multiple of 2 and 3 is 6 so turn all fractions into sixths Special form of 1

Lowest common denominator is 10 so make all fractions tenths

Turn both fractions into twelfths

What is the lowest number BOTH 3 and 7 divide into? Finally the fractions are READY to add. I just have to add the numerators 9+14=23 It is 3/3 So I multiply 3/7 by 3/3 It is 7/7 So I multiply 2/3 by 7/7 What is the lowest number BOTH 3 and 7 divide into? Hmmmmm?????? What special form of 1 will change 7 to 21. Hmmmm? What special form of 1 will change 3 to 21. Hmmmm? It is 21. So that is my common denominator Now 3x3=9 and 2x7=14 Now I know the new numerators

Adding Mixed Numbers Separate the fraction and the whole number sections, add them separately and recombine at the end

LET’S TRY 3 2 - + 4 5 7 5 12 8 5 7 6 10 8 1 9 2

Working with a partner, stand at the problem you are assigned PROBLEM HUNT Working with a partner, stand at the problem you are assigned Write down the solution to your problem on your graphic organizer Look around the room for that solution on a sticky note to show what question you need to move to Both partners need to have the answers down and SHOW THEIR WORK!

DOL: 4 1 + - 5 2 5 1 6 2 4 1 5 3 9 1 10 2

DOL: 4 1 13 + - 5 2 10 5 1 2 1 6 2 6 3 4 1 7 5 3 15 9 1 14 7 10 2 10 5