Multliplying Fractions with Whole Numbers Day 2
Objective
Big Idea
Number Hook - Magic Trick
Math magic tricks can liven up any math class and create a sense of wonder and curiosity about math. Not only that, math magic creates a new context for algebraic reasoning as students go beyond "What's the answer?" to explore "What's the trick?"
Many math magic tricks call on students to compute with the four basic operations -- sometimes applied to very large numbers. In the context of math magic, computational practice is fun.
If a trick works for some students and not others, it's amazing how eager they can be to find and fix their mistakes so the trick will come out right.
Best of all, many students have an inner motivation to understand how math magic tricks work, and that curiosity can lead them to embrace and apply both new and familiar concepts and skills, including algebra.
23 Skidoo
To do this number trick students will pick any three digit number.
Then add 25 to it.
Next, multiply the sum by 2.
Then subtract 4.
Next, divide the answer by 2.
Then subtract your three digit number from this answer
The answer is 23!!
Warm Up
For this warm up I give my students a true false question. My students will see questions similar to this when they take the Smarter Balance test this spring. (PARCC also has questions like this) My students must be comfortable proving and conjecturing about math. This is an excellent way to get my students used to doing this.
I give my students this question:
True or False? Why?
4/9 > 3/7
Concept development
I begin this lesson by telling students that they will work with their learning partners to use the skills they learned yesterday to solve problems involving fractions and whole numbers. I pre-select five problems from this resource, (wholenumberxfractionwordproblems.pdf) and then let each partner select three of the five they want to solve for today's work. Letting students select the problems they want gives students choice and ownership in their learning, but also serves as a way for me to use the other two problems for early finishers.
Students work for about 25 minutes to solve the three problems. Each problem is solved on a separate piece of paper so students can then hang up their work for a gallery walk when finished.
Listen in as this student is working to solve a problem.
You can see and hear this student thinking through a problem. In the very beginning you also hear him ask me if the denominator changes when adding fractions. My response was, "I don't know, you tell me." As often as I can and try to not always answer my students questions with a direct answer, but encourage them to think about the question they asked.
After most students are done, and the 25 minutes has elapsed, I instruct all students to hang up their work and prepare for the gallery walk.
Gallery walks are a great way to get students out of their seats and moving around the classroom. Some teachers shudder at the thought of having all of the students out of their desks moving around the classroom at the same time, but in actuality, it can be a very effective technique for classroom management. Your kinesthetic learners need a certain amount of time out of their seats, and this will give them that opportunity. The most important thing to remember is to establish expectations before beginning the activity. Keep reading for some information on gallery walks, as well as some ideas for incorporating them into your classroom.
One way I like to end gallery walks is to have each student go around the room and be able to, (if they want) to say one thing they learned from the gallery walk. In the beginning of the year, many students are reluctant to say anything during this ending wrap up, but with practice, confidence gained, by the end of the year, students almost always want to say what they learned.
