Sharing Brownies

SOL Number and Number Sense

3.3 The student will  a.) divide regions and sets to represent a fraction; and b.) name and write the fractions represented by a given model (area/region, length/measurement, and sent). Fractions (including mixed numbers) include halves, thirds, fourths, eighths, and tenths.

Goals:Students will be able to demonstrate an understanding of mixed numbers using words or pictures.
Students will use: problem-solving, mathematical communication, mathematical reasoning connections, mathematical representations

• Solidifying the concept of whole and equal parts, and introducing the concept of mixed numbers
•  Students will have been exposed to the concept of a whole, and that fractions are used to name parts of a set.

Key math vocabulary: whole, half, one-fourth or a quarter, equal, sharing, fractions

Refer back to previous sharing experience – Remembering Roberto’s birthday cupcakes. “Were there exactly the right amount? (There were leftovers) What if we wanted to eat all of the cupcakes, and make sure that everyone gets a fair share? Today we are going to introduce another Fair Share problem, but this time, we won’t have any leftovers, we are going to us fractions to show how the leftovers will be shared equally.”

Students at the carpet will be asked to divide one brownie between four people equally. Students will think-pair-share ideas to solve the problem.Teacher will select students who have the right idea based on what teacher hears.Teacher records accurate pictorial representation and numeric representation within a sentence frame “Each person gets ¼ of the whole brownie” for students to use as reference during the next task.ANTICIPATE: Possible Solutions for 4 people, 5 brownie sharing problem:

Possible solution 1: Explains as each person receiving 5/20 of a brownie.

Possible solution 2: Explains as each person receiving 5/4 of a brownie

Possible solution 3: Explains as each person receiving 1 ¼ of a brownie

Possible solution 4: Explains as each person receiving 1 ¼ of a brownie.

Methods may include:.

• Dealing out the brownies like cards and dividing the last brownie into halves or 4ths.
• Using an algorithm.
• Saying that there is one left over.
• Drawing pictures.

Possible misconceptions:
Confusing the numerator with the denominator.
Once a brownie is divided, the parts are now wholes.
The last brownie cannot be divided.

How did you get 20? What does 20 represent?
Are those 20 pieces whole brownies? Or are they
fractions of brownies?

Resources:
1. Paper brownies
2. Scissors
3. Drawing paper
4. Markers
5. Chart paper
6. 5 sentence strips with pre-written sentence frame “Each person gets _______.”

Students will work individually and in pairs by ability and motivation. Students will record their work on the drawing paper.