Comstock Park — Marshmallows, math and hot cocoa created the perfect equation for a little multiplication on a snowy Friday morning at Pine Island Elementary.
Students in Rachel Haveman’s third-grade class spent about an hour using mini marshmallows to learn about a math tool they could use to help solve multiplication problems. Their reward was a cup of hot cocoa — with marshmallows, of course — to sip while coloring their own paper mug.
To get the fun started, Haveman distributed about a third of a cup of marshmallows to each student. She then explained that the students would use the marshmallows to build something called a math array.
A math array is a visual representation of numbers or objects arranged in rows and columns, where each row contains the same number of items creating a rectangular pattern. Once the pattern is complete, the student counts each dot for the answer.
For example, 3×4 would be arranged as three rows with four items in each row. The student would draw four horizontal rows with three dots, and then count all the dots to come up with the answer of 12.
Counting the Marshmallows
At the students’ suggestion, Haveman wrote “5×4” on the board. She pointed out that the five would be the number of rows the students would need and the four would be the number of columns.
Third-grader Sofia Chinchilla demonstrated the process by carefully counting out five mini marshmallows and arranging them in a straight line.
She then placed three more marshmallows next to the first marshmallow in the line; from there, she filled in the following rows with the goal of including four marshmallows in each row.
After counting her marshmallows, Sofia first came up with the answer of 17, but immediately said she knew that was not correct. She studied her marshmallow array to try to find the problem.
“I didn’t have the middle filled in right,” Sofia said and made the correction, coming up with the correct answer of 20.
After practicing with their own arrays, the students paired up to challenge each other. First, each student wrote a multiplication problem on their white board and the other student created a math array based on that equation. The students took turns making an array with the other student figuring out the math equation.
“I’m not going to take it easy on you,” said Connor Basel to his partner, Flynn Wilkinson.
Connor considered the number of marshmallows on the table in front of Flynn and then wrote “12×4” on his board, intending to challenge him with a large number. Flynn laid out 12 rows of marshmallows, then placed four more in each column to solve the problem.
“The purpose of this is not so much for the students to learn the multiplication tables, but to give them another strategy they can use if they get stuck trying to solve a problem,” Haveman said, adding that the array method can also be used for division, addition and subtraction. “Relating it to the season by using the marshmallows makes the strategy more fun.”
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