Day 54: Dividing by Multiplying by the Reciprocal

6th Grade Math Standards: 6.NS.1 Interpret and compute quotients of fractions, and solve word problems involving division of fractions by fractions, e.g., by using visual fraction models and equations to represent the problem. For example, create a story context for (2/3) ÷ (3/4) and use a visual fraction model to show the quotient; use the relationship between multiplication and division to explain that (2/3) ÷ (3/4) = 8/9 because 3/4 of 8/9 is 2/3. (In general, (a/b) ÷ (c/d) = ad/bc .) How much chocolate will each person get if 3 people share 1/2 lb of chocolate equally? How many 3/4-cup servings are in 2/3 of a cup of yogurt? How wide is a rectangular strip of land with length 3/4 mi and area 1/2 square mi?

Objective: Divide fractions by multiplying by the reciprocal of the divisor

Agenda:

1. Open Middle find a quotient of 1/20 
2. QSSQ
3. Review the homework
4. Reciprocals
5. Show students the difference between 6 divided by 2 and half of 6
6. Dividing by Multiplying by the reciprocal practice 

Assessment: I had students stand up when they tried multiplying by the reciprocal problems on their own; checking the homework

Glass Half-Full: The open middle problem was solved by the students, but not me. I gave up after five minutes and checked the solution to see if it was as hard as I was making it. I couldn't do it without using a whole number or improper fraction cause my brain was on Thanksgiving. When I saw the answers, I saw that I might not be qualified to teach mathematics since I gave up and since it was very very easy. When the students were able to do the problem with pretty high efficiency, it was confirmed that I should be thankful that I have a job because at times they could definitely take the mic from me.

Regrets: When students stood up, they had the correct answer, but were still finding a common denominator. Is there anything wrong with that? To me, this is one of those situations where maybe adding a tool to the toolbox is not a big deal.

Link: The most fun cities. Just for the record I've been to 7 of the best 10 and 4 of the best 5.