Adding, Subtracting, Multiplying and Dividing Fractions Word Learning to Understand Word Problems Problem #WCW Wednesdays Adding, Subtracting, Multiplying and Dividing Fractions

Question: The grocer gave you 5/9 of a bunch of bananas Question: The grocer gave you 5/9 of a bunch of bananas. You already had 2/9 of a bunch in your bag. Do you now have a whole bunch in your bag? This problem has two parts. You need to figure out how much of a bunch you now have and then you have to figure out if it is greater than a full bunch. How much do you have? 5/9 + 2/9 = ? Do they have common denominators? Yes What order of operation is needed? Addition Add numerators? 5+2 Answer: 7/9 Do you have a whole bunch? No

Question: You have a bag with 8 marbles Question: You have a bag with 8 marbles. The bag can hold a maximum of 12 marbles. You let your friend borrow 3 marbles. What fraction of the bag do you have left? Strategy: You weren't given a direct fraction in this problem. Can you see how you have 8/12 of a bag and you have to give up 3/12 of a bag? You were given two values: 8 and 3. The possible number of marbles is 12 for each value. How much do you have? 8/12 - 3/12=? Do they have common denominators? Yes What order of operation is needed? Subtraction Add numerators? 8-3=5 Answer: 5/12 Do you have a whole bunch? 5/12 of a bag of marbles

Multiplication Question: A carpenter is fixing a house Multiplication Question: A carpenter is fixing a house. He needs to cut some beams. He will be sawing off 2/3 of a six and a half foot beam. How much will he be sawing off? Strategy: Remember that multiplication word problems usually use the word "of". You might have "one half of six" or "2/3 of 9". That should help you figure out when you need to multiply. We're also using some words instead of numerals in the problem. You need to figure out how the numbers will look. The question is asking how much he will saw off. You have one fraction multiplied by a mixed number.

Multiplying Fractions: cont. How many feet of the beam is he sawing off? 2/3 * 6 1/2 = ? Convert to improper fractions: 6 1/2 = 6 + 1/2 = 12/2 + 1/2 = 13/2 Rewrite problem: 2/3 * 13/2= Multiply numerator by numerator & denominator by denominator. New fraction 26/6 Convert to a mixed number 4 2/6 He will saw off 4 1/3 feet of the beam

Question: There are 12 kids at a birthday party Question: There are 12 kids at a birthday party. There are three and a half pies and everyone will get an equal amount of pie. How much pie does each kid get? Strategy: This is a division problem. We are taking a big amount and dividing it up for a bunch of people. We have a mixed number being divided by a whole number. Try to convert the whole number and the mixed number into improper fractions. Then you can go through the normal steps of division for fractions.

Dividing Fractions… cont. 3 ½ / 12 = ? Convert 3 ½ to a improper fraction. 7/2 Rewrite: 7/2 divided by 12/1 Reciprocal of the 2nd fraction 1/12 Change sign to multiplication Solve 7/24 Answer Each kid gets 7/24 of a pie.