Dividing Using Mental Math
Mrs. Dewey wrote this problem on the board.
“What is a story that might make sense for this problem?” she asked.
“How about baseball?” said John. “If there are 243 total players and there are 9 players on a team, how many teams would you have?”
“That sounds good. Let's first write this division problem as a multiplication problem.” Mrs. Dewey wrote this on the board.
“Sometimes it is helpful to write number sentences we know to help us solve division problems.” Mrs. Dewey wrote some number sentences on the board.
“Which of these might be helpful for solving the problem?” asked Mrs. Dewey.
“I would use 9 20 = 180, 9 30 = 270, and 9 5 = 45,” said Lee Yah.
“I would use 9 30 = 270 and 27 ÷ 9 = 3,” said Keenya. Both Lee Yah and Keenya shared their reasoning.