Skip to main content
Category

Word Problems

DecimalsGeneral InterestMultiplicationNumber and OperationsNumerical ReasoningReal-World ProblemsVideosWord Problems

When You Multiply by 10, Just Add a Zero? Horrors!?!

Have you ever asked students to solve 12.6 x 10, and they respond that the answer is 12.60? I have, many times. Students who do this apply a pattern that works when they multiply whole numbers by 10—they tack on a zero to the end of the number they’re multiplying. But then they apply the same pattern when working with decimals. What can we do?
Marilyn Burns
October 1, 2018
DivisionGeneral InterestNumber and OperationsNumerical ReasoningReal-World ProblemsSilent MathWord Problems

One Lesson, Two Pedagogical Mistakes

I believe strongly that mistakes are learning opportunities. At least that’s what I regularly tell students. But it sometimes feels different when the mistakes are mine . . . and especially when they are pedagogical mistakes that I make while teaching. That happened to me recently when teaching a lesson to fourth graders.
Marilyn Burns
January 1, 2018
AssessmentBooks by MarilynDivisionGeneral InterestMath and LiteratureMultiplicationNumber and OperationsNumerical ReasoningProblem SolvingWord Problems

One Lesson, Three Grades, Three Twists

The children's book 17 Kings and 42 Elephants by Margaret Mahy is one of my long-time favorites. In this post I describe a division lesson that I’ve taught to third graders but recently revisited with fourth- and fifth-grade classes. With the older students, we tried extensions that differentiated the experience and put students in charge of deciding on problems for themselves. It was exciting to me to expand a lesson I've taught many times into a multi-day investigation.
Marilyn Burns
January 30, 2017
General InterestNumber and OperationsProblem SolvingReal-World ProblemsWord Problems

Where’s the Math?

Students’ ideas often amaze me, and Lydia’s is one of the most suprising examples. She used 7 x 3 = 21 to figure out that 8 x 4 = 32. She reasoned that since the factors in 7 x 3 were each 1 less than the factors in 8 x 4, she’d just increase each digit in the answer, changing 21 to 32. She was correct! Read about Lydia's discovery, what I did, and what I learned.
Marilyn Burns
May 11, 2015