While working on DynaMath, I’ve worked on a LOT of word problems. I’m with your students; I wish there was a fast, fail-safe method for solving word problems. (Even better, a fast, fail-safe method for WRITING them!) But take it from me: There’s no substitute for thinking.
Using keywords—associating particular words with certain operations—may seem like a quick and straightforward problem-solving strategy. I was surprised to learn that we should be wary of teaching them. Here’s why:
1. Keywords can be misleading. Word problems are all about context. Focusing on specific words (rather than on what’s happening in the problem) can lead students to use an incorrect operation. Consider this: “There are 63 pencil cases in a box, and I ordered 15 boxes. How many pencil cases do I have altogether?” Most keyword charts list “altogether” as a keyword for addition. But adding the numbers in this problem would be incorrect.
2. Some problems don’t have any keywords. For example, “How many legs do 7 elephants have?” does not have a keyword. However, any first-grader should be able to solve the problem by thinking and drawing a picture or building a model.
3. Thinking should come first. The most important strategy when problem solving is to think critically about what the problem is asking. A reliance on keywords can encourage students to ignore a problem’s meaning and look for a problem-solving formula.
When teaching word problems, we can help students by:
- Asking them to retell the problem/story in their own words. Ask: “What is happening in this problem/story?”
- Encouraging them to make sense of the mathematical situation. For example, “Do you think the answer is going to be more or less than the numbers in the problem? Why do you think that?”
- Encouraging the use of visual models: “What picture could you draw to show what is happening in this problem?”
Do you have any other favorite strategies for promoting meaningful thinking about word problems in your classroom? E-mail me, I would love to hear them!